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2017-06-14KVM: arm/arm64: Handle possible NULL stage2 pud when ageing pagesMarc Zyngier
commit d6dbdd3c8558cad3b6d74cc357b408622d122331 upstream. Under memory pressure, we start ageing pages, which amounts to parsing the page tables. Since we don't want to allocate any extra level, we pass NULL for our private allocation cache. Which means that stage2_get_pud() is allowed to fail. This results in the following splat: [ 1520.409577] Unable to handle kernel NULL pointer dereference at virtual address 00000008 [ 1520.417741] pgd = ffff810f52fef000 [ 1520.421201] [00000008] *pgd=0000010f636c5003, *pud=0000010f56f48003, *pmd=0000000000000000 [ 1520.429546] Internal error: Oops: 96000006 [#1] PREEMPT SMP [ 1520.435156] Modules linked in: [ 1520.438246] CPU: 15 PID: 53550 Comm: qemu-system-aar Tainted: G W 4.12.0-rc4-00027-g1885c397eaec #7205 [ 1520.448705] Hardware name: FOXCONN R2-1221R-A4/C2U4N_MB, BIOS G31FB12A 10/26/2016 [ 1520.463726] task: ffff800ac5fb4e00 task.stack: ffff800ce04e0000 [ 1520.469666] PC is at stage2_get_pmd+0x34/0x110 [ 1520.474119] LR is at kvm_age_hva_handler+0x44/0xf0 [ 1520.478917] pc : [<ffff0000080b137c>] lr : [<ffff0000080b149c>] pstate: 40000145 [ 1520.486325] sp : ffff800ce04e33d0 [ 1520.489644] x29: ffff800ce04e33d0 x28: 0000000ffff40064 [ 1520.494967] x27: 0000ffff27e00000 x26: 0000000000000000 [ 1520.500289] x25: ffff81051ba65008 x24: 0000ffff40065000 [ 1520.505618] x23: 0000ffff40064000 x22: 0000000000000000 [ 1520.510947] x21: ffff810f52b20000 x20: 0000000000000000 [ 1520.516274] x19: 0000000058264000 x18: 0000000000000000 [ 1520.521603] x17: 0000ffffa6fe7438 x16: ffff000008278b70 [ 1520.526940] x15: 000028ccd8000000 x14: 0000000000000008 [ 1520.532264] x13: ffff7e0018298000 x12: 0000000000000002 [ 1520.537582] x11: ffff000009241b93 x10: 0000000000000940 [ 1520.542908] x9 : ffff0000092ef800 x8 : 0000000000000200 [ 1520.548229] x7 : ffff800ce04e36a8 x6 : 0000000000000000 [ 1520.553552] x5 : 0000000000000001 x4 : 0000000000000000 [ 1520.558873] x3 : 0000000000000000 x2 : 0000000000000008 [ 1520.571696] x1 : ffff000008fd5000 x0 : ffff0000080b149c [ 1520.577039] Process qemu-system-aar (pid: 53550, stack limit = 0xffff800ce04e0000) [...] [ 1521.510735] [<ffff0000080b137c>] stage2_get_pmd+0x34/0x110 [ 1521.516221] [<ffff0000080b149c>] kvm_age_hva_handler+0x44/0xf0 [ 1521.522054] [<ffff0000080b0610>] handle_hva_to_gpa+0xb8/0xe8 [ 1521.527716] [<ffff0000080b3434>] kvm_age_hva+0x44/0xf0 [ 1521.532854] [<ffff0000080a58b0>] kvm_mmu_notifier_clear_flush_young+0x70/0xc0 [ 1521.539992] [<ffff000008238378>] __mmu_notifier_clear_flush_young+0x88/0xd0 [ 1521.546958] [<ffff00000821eca0>] page_referenced_one+0xf0/0x188 [ 1521.552881] [<ffff00000821f36c>] rmap_walk_anon+0xec/0x250 [ 1521.558370] [<ffff000008220f78>] rmap_walk+0x78/0xa0 [ 1521.563337] [<ffff000008221104>] page_referenced+0x164/0x180 [ 1521.569002] [<ffff0000081f1af0>] shrink_active_list+0x178/0x3b8 [ 1521.574922] [<ffff0000081f2058>] shrink_node_memcg+0x328/0x600 [ 1521.580758] [<ffff0000081f23f4>] shrink_node+0xc4/0x328 [ 1521.585986] [<ffff0000081f2718>] do_try_to_free_pages+0xc0/0x340 [ 1521.592000] [<ffff0000081f2a64>] try_to_free_pages+0xcc/0x240 [...] The trivial fix is to handle this NULL pud value early, rather than dereferencing it blindly. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-14arm: KVM: Allow unaligned accesses at HYPMarc Zyngier
commit 33b5c38852b29736f3b472dd095c9a18ec22746f upstream. We currently have the HSCTLR.A bit set, trapping unaligned accesses at HYP, but we're not really prepared to deal with it. Since the rest of the kernel is pretty happy about that, let's follow its example and set HSCTLR.A to zero. Modern CPUs don't really care. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-20KVM: arm/arm64: fix races in kvm_psci_vcpu_onAndrew Jones
commit 6c7a5dce22b3f3cc44be098e2837fa6797edb8b8 upstream. Fix potential races in kvm_psci_vcpu_on() by taking the kvm->lock mutex. In general, it's a bad idea to allow more than one PSCI_CPU_ON to process the same target VCPU at the same time. One such problem that may arise is that one PSCI_CPU_ON could be resetting the target vcpu, which fills the entire sys_regs array with a temporary value including the MPIDR register, while another looks up the VCPU based on the MPIDR value, resulting in no target VCPU found. Resolves both races found with the kvm-unit-tests/arm/psci unit test. Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <cdall@linaro.org> Reported-by: Levente Kurusa <lkurusa@redhat.com> Suggested-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-27kvm: arm/arm64: Fix locking for kvm_free_stage2_pgdSuzuki K Poulose
commit 8b3405e345b5a098101b0c31b264c812bba045d9 upstream. In kvm_free_stage2_pgd() we don't hold the kvm->mmu_lock while calling unmap_stage2_range() on the entire memory range for the guest. This could cause problems with other callers (e.g, munmap on a memslot) trying to unmap a range. And since we have to unmap the entire Guest memory range holding a spinlock, make sure we yield the lock if necessary, after we unmap each PUD range. Fixes: commit d5d8184d35c9 ("KVM: ARM: Memory virtualization setup") Cc: Paolo Bonzini <pbonzin@redhat.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Christoffer Dall <christoffer.dall@linaro.org> Cc: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> [ Avoid vCPU starvation and lockup detector warnings ] Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-12arm/arm64: KVM: Take mmap_sem in kvm_arch_prepare_memory_regionMarc Zyngier
commit 72f310481a08db821b614e7b5d00febcc9064b36 upstream. We don't hold the mmap_sem while searching for VMAs (via find_vma), in kvm_arch_prepare_memory_region, which can end up in expected failures. Fixes: commit 8eef91239e57 ("arm/arm64: KVM: map MMIO regions at creation time") Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Eric Auger <eric.auger@rehat.com> Reviewed-by: Christoffer Dall <cdall@linaro.org> [ Handle dirty page logging failure case ] Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-12arm/arm64: KVM: Take mmap_sem in stage2_unmap_vmMarc Zyngier
commit 90f6e150e44a0dc3883110eeb3ab35d1be42b6bb upstream. We don't hold the mmap_sem while searching for the VMAs when we try to unmap each memslot for a VM. Fix this properly to avoid unexpected results. Fixes: commit 957db105c997 ("arm/arm64: KVM: Introduce stage2_unmap_vm") Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-09-24kvm-arm: Unmap shadow pagetables properlySuzuki K Poulose
commit 293f293637b55db4f9f522a5a72514e98a541076 upstream. On arm/arm64, we depend on the kvm_unmap_hva* callbacks (via mmu_notifiers::invalidate_*) to unmap the stage2 pagetables when the userspace buffer gets unmapped. However, when the Hypervisor process exits without explicit unmap of the guest buffers, the only notifier we get is kvm_arch_flush_shadow_all() (via mmu_notifier::release ) which does nothing on arm. Later this causes us to access pages that were already released [via exit_mmap() -> unmap_vmas()] when we actually get to unmap the stage2 pagetable [via kvm_arch_destroy_vm() -> kvm_free_stage2_pgd()]. This triggers crashes with CONFIG_DEBUG_PAGEALLOC, which unmaps any free'd pages from the linear map. [ 757.644120] Unable to handle kernel paging request at virtual address ffff800661e00000 [ 757.652046] pgd = ffff20000b1a2000 [ 757.655471] [ffff800661e00000] *pgd=00000047fffe3003, *pud=00000047fcd8c003, *pmd=00000047fcc7c003, *pte=00e8004661e00712 [ 757.666492] Internal error: Oops: 96000147 [#3] PREEMPT SMP [ 757.672041] Modules linked in: [ 757.675100] CPU: 7 PID: 3630 Comm: qemu-system-aar Tainted: G D 4.8.0-rc1 #3 [ 757.683240] Hardware name: AppliedMicro X-Gene Mustang Board/X-Gene Mustang Board, BIOS 3.06.15 Aug 19 2016 [ 757.692938] task: ffff80069cdd3580 task.stack: ffff8006adb7c000 [ 757.698840] PC is at __flush_dcache_area+0x1c/0x40 [ 757.703613] LR is at kvm_flush_dcache_pmd+0x60/0x70 [ 757.708469] pc : [<ffff20000809dbdc>] lr : [<ffff2000080b4a70>] pstate: 20000145 ... [ 758.357249] [<ffff20000809dbdc>] __flush_dcache_area+0x1c/0x40 [ 758.363059] [<ffff2000080b6748>] unmap_stage2_range+0x458/0x5f0 [ 758.368954] [<ffff2000080b708c>] kvm_free_stage2_pgd+0x34/0x60 [ 758.374761] [<ffff2000080b2280>] kvm_arch_destroy_vm+0x20/0x68 [ 758.380570] [<ffff2000080aa330>] kvm_put_kvm+0x210/0x358 [ 758.385860] [<ffff2000080aa524>] kvm_vm_release+0x2c/0x40 [ 758.391239] [<ffff2000082ad234>] __fput+0x114/0x2e8 [ 758.396096] [<ffff2000082ad46c>] ____fput+0xc/0x18 [ 758.400869] [<ffff200008104658>] task_work_run+0x108/0x138 [ 758.406332] [<ffff2000080dc8ec>] do_exit+0x48c/0x10e8 [ 758.411363] [<ffff2000080dd5fc>] do_group_exit+0x6c/0x130 [ 758.416739] [<ffff2000080ed924>] get_signal+0x284/0xa18 [ 758.421943] [<ffff20000808a098>] do_signal+0x158/0x860 [ 758.427060] [<ffff20000808aad4>] do_notify_resume+0x6c/0x88 [ 758.432608] [<ffff200008083624>] work_pending+0x10/0x14 [ 758.437812] Code: 9ac32042 8b010001 d1000443 8a230000 (d50b7e20) This patch fixes the issue by moving the kvm_free_stage2_pgd() to kvm_arch_flush_shadow_all(). Tested-by: Itaru Kitayama <itaru.kitayama@riken.jp> Reported-by: Itaru Kitayama <itaru.kitayama@riken.jp> Reported-by: James Morse <james.morse@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-06-01arm/arm64: KVM: Enforce Break-Before-Make on Stage-2 page tablesMarc Zyngier
commit d4b9e0790aa764c0b01e18d4e8d33e93ba36d51f upstream. The ARM architecture mandates that when changing a page table entry from a valid entry to another valid entry, an invalid entry is first written, TLB invalidated, and only then the new entry being written. The current code doesn't respect this, directly writing the new entry and only then invalidating TLBs. Let's fix it up. Reported-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-09arm/arm64: KVM: Fix ioctl error handlingMichael S. Tsirkin
commit 4cad67fca3fc952d6f2ed9e799621f07666a560f upstream. Calling return copy_to_user(...) in an ioctl will not do the right thing if there's a pagefault: copy_to_user returns the number of bytes not copied in this case. Fix up kvm to do return copy_to_user(...)) ? -EFAULT : 0; everywhere. Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-04ARM/arm64: KVM: correct PTE uncachedness checkArd Biesheuvel
Commit e6fab5442345 ("ARM/arm64: KVM: test properly for a PTE's uncachedness") modified the logic to test whether a HYP or stage-2 mapping needs flushing, from [incorrectly] interpreting the page table attributes to [incorrectly] checking whether the PFN that backs the mapping is covered by host system RAM. The PFN number is part of the output of the translation, not the input, so we have to use pte_pfn() on the contents of the PTE, not __phys_to_pfn() on the HYP virtual address or stage-2 intermediate physical address. Fixes: e6fab5442345 ("ARM/arm64: KVM: test properly for a PTE's uncachedness") Cc: stable@vger.kernel.org Tested-by: Pavel Fedin <p.fedin@samsung.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-12-04arm64: KVM: Get rid of old vcpu_reg()Pavel Fedin
Using oldstyle vcpu_reg() accessor is proven to be inappropriate and unsafe on ARM64. This patch converts the rest of use cases to new accessors and completely removes vcpu_reg() on ARM64. Signed-off-by: Pavel Fedin <p.fedin@samsung.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-12-04arm64: KVM: Correctly handle zero register during MMIOPavel Fedin
On ARM64 register index of 31 corresponds to both zero register and SP. However, all memory access instructions, use ZR as transfer register. SP is used only as a base register in indirect memory addressing, or by register-register arithmetics, which cannot be trapped here. Correct emulation is achieved by introducing new register accessor functions, which can do special handling for reg_num == 31. These new accessors intentionally do not rely on old vcpu_reg() on ARM64, because it is to be removed. Since the affected code is shared by both ARM flavours, implementations of these accessors are also added to ARM32 code. This patch fixes setting MMIO register to a random value (actually SP) instead of zero by something like: *((volatile int *)reg) = 0; compilers tend to generate "str wzr, [xx]" here [Marc: Fixed 32bit splat] Signed-off-by: Pavel Fedin <p.fedin@samsung.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-11-24KVM: arm/arm64: Fix preemptible timer active state crazynessChristoffer Dall
We were setting the physical active state on the GIC distributor in a preemptible section, which could cause us to set the active state on different physical CPU from the one we were actually going to run on, hacoc ensues. Since we are no longer descheduling/scheduling soft timers in the flush/sync timer functions, simply moving the timer flush into a non-preemptible section. Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-11-24ARM/arm64: KVM: test properly for a PTE's uncachednessArd Biesheuvel
The open coded tests for checking whether a PTE maps a page as uncached use a flawed '(pte_val(xxx) & CONST) != CONST' pattern, which is not guaranteed to work since the type of a mapping is not a set of mutually exclusive bits For HYP mappings, the type is an index into the MAIR table (i.e, the index itself does not contain any information whatsoever about the type of the mapping), and for stage-2 mappings it is a bit field where normal memory and device types are defined as follows: #define MT_S2_NORMAL 0xf #define MT_S2_DEVICE_nGnRE 0x1 I.e., masking *and* comparing with the latter matches on the former, and we have been getting lucky merely because the S2 device mappings also have the PTE_UXN bit set, or we would misidentify memory mappings as device mappings. Since the unmap_range() code path (which contains one instance of the flawed test) is used both for HYP mappings and stage-2 mappings, and considering the difference between the two, it is non-trivial to fix this by rewriting the tests in place, as it would involve passing down the type of mapping through all the functions. However, since HYP mappings and stage-2 mappings both deal with host physical addresses, we can simply check whether the mapping is backed by memory that is managed by the host kernel, and only perform the D-cache maintenance if this is the case. Cc: stable@vger.kernel.org Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Pavel Fedin <p.fedin@samsung.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22arm/arm64: KVM: Improve kvm_exit tracepointChristoffer Dall
The ARM architecture only saves the exit class to the HSR (ESR_EL2 for arm64) on synchronous exceptions, not on asynchronous exceptions like an IRQ. However, we only report the exception class on kvm_exit, which is confusing because an IRQ looks like it exited at some PC with the same reason as the previous exit. Add a lookup table for the exception index and prepend the kvm_exit tracepoint text with the exception type to clarify this situation. Also resolve the exception class (EC) to a human-friendly text version so the trace output becomes immediately usable for debugging this code. Cc: Wei Huang <wei@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22KVM: arm/arm64: implement kvm_arm_[halt,resume]_guestEric Auger
We introduce kvm_arm_halt_guest and resume functions. They will be used for IRQ forward state change. Halt is synchronous and prevents the guest from being re-entered. We use the same mechanism put in place for PSCI former pause, now renamed power_off. A new flag is introduced in arch vcpu state, pause, only meant to be used by those functions. Signed-off-by: Eric Auger <eric.auger@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22KVM: arm/arm64: check power_off in critical section before VCPU runEric Auger
In case a vcpu off PSCI call is called just after we executed the vcpu_sleep check, we can enter the guest although power_off is set. Let's check the power_off state in the critical section, just before entering the guest. Signed-off-by: Eric Auger <eric.auger@linaro.org> Reported-by: Christoffer Dall <christoffer.dall@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22KVM: arm/arm64: check power_off in kvm_arch_vcpu_runnableEric Auger
kvm_arch_vcpu_runnable now also checks whether the power_off flag is set. Signed-off-by: Eric Auger <eric.auger@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22KVM: arm/arm64: rename pause into power_offEric Auger
The kvm_vcpu_arch pause field is renamed into power_off to prepare for the introduction of a new pause field. Also vcpu_pause is renamed into vcpu_sleep since we will sleep until both power_off and pause are false. Signed-off-by: Eric Auger <eric.auger@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22arm/arm64: KVM : Enable vhost device selection under KVM config menuWei Huang
vhost drivers provide guest VMs with better I/O performance and lower CPU utilization. This patch allows users to select vhost devices under KVM configuration menu on ARM. This makes vhost support on arm/arm64 on a par with other architectures (e.g. x86, ppc). Signed-off-by: Wei Huang <wei@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22arm/arm64: KVM: Rework the arch timer to use level-triggered semanticsChristoffer Dall
The arch timer currently uses edge-triggered semantics in the sense that the line is never sampled by the vgic and lowering the line from the timer to the vgic doesn't have any effect on the pending state of virtual interrupts in the vgic. This means that we do not support a guest with the otherwise valid behavior of (1) disable interrupts (2) enable the timer (3) disable the timer (4) enable interrupts. Such a guest would validly not expect to see any interrupts on real hardware, but will see interrupts on KVM. This patch fixes this shortcoming through the following series of changes. First, we change the flow of the timer/vgic sync/flush operations. Now the timer is always flushed/synced before the vgic, because the vgic samples the state of the timer output. This has the implication that we move the timer operations in to non-preempible sections, but that is fine after the previous commit getting rid of hrtimer schedules on every entry/exit. Second, we change the internal behavior of the timer, letting the timer keep track of its previous output state, and only lower/raise the line to the vgic when the state changes. Note that in theory this could have been accomplished more simply by signalling the vgic every time the state *potentially* changed, but we don't want to be hitting the vgic more often than necessary. Third, we get rid of the use of the map->active field in the vgic and instead simply set the interrupt as active on the physical distributor whenever the input to the GIC is asserted and conversely clear the physical active state when the input to the GIC is deasserted. Fourth, and finally, we now initialize the timer PPIs (and all the other unused PPIs for now), to be level-triggered, and modify the sync code to sample the line state on HW sync and re-inject a new interrupt if it is still pending at that time. Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22arm/arm64: KVM: arch_timer: Only schedule soft timer on vcpu_blockChristoffer Dall
We currently schedule a soft timer every time we exit the guest if the timer did not expire while running the guest. This is really not necessary, because the only work we do in the timer work function is to kick the vcpu. Kicking the vcpu does two things: (1) If the vpcu thread is on a waitqueue, make it runnable and remove it from the waitqueue. (2) If the vcpu is running on a different physical CPU from the one doing the kick, it sends a reschedule IPI. The second case cannot happen, because the soft timer is only ever scheduled when the vcpu is not running. The first case is only relevant when the vcpu thread is on a waitqueue, which is only the case when the vcpu thread has called kvm_vcpu_block(). Therefore, we only need to make sure a timer is scheduled for kvm_vcpu_block(), which we do by encapsulating all calls to kvm_vcpu_block() with kvm_timer_{un}schedule calls. Additionally, we only schedule a soft timer if the timer is enabled and unmasked, since it is useless otherwise. Note that theoretically userspace can use the SET_ONE_REG interface to change registers that should cause the timer to fire, even if the vcpu is blocked without a scheduled timer, but this case was not supported before this patch and we leave it for future work for now. Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-20KVM: arm: use GIC support unconditionallyArnd Bergmann
The vgic code on ARM is built for all configurations that enable KVM, but the parent_data field that it references is only present when CONFIG_IRQ_DOMAIN_HIERARCHY is set: virt/kvm/arm/vgic.c: In function 'kvm_vgic_map_phys_irq': virt/kvm/arm/vgic.c:1781:13: error: 'struct irq_data' has no member named 'parent_data' This flag is implied by the GIC driver, and indeed the VGIC code only makes sense if a GIC is present. This changes the CONFIG_KVM symbol to always select GIC, which avoids the issue. Fixes: 662d9715840 ("arm/arm64: KVM: Kill CONFIG_KVM_ARM_{VGIC,TIMER}") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-20KVM: arm/arm64: Fix memory leak if timer initialization failsPavel Fedin
Jump to correct label and free kvm_host_cpu_state Reviewed-by: Wei Huang <wei@redhat.com> Signed-off-by: Pavel Fedin <p.fedin@samsung.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-09-17arm/arm64: KVM: Remove 'config KVM_ARM_MAX_VCPUS'Ming Lei
This patch removes config option of KVM_ARM_MAX_VCPUS, and like other ARCHs, just choose the maximum allowed value from hardware, and follows the reasons: 1) from distribution view, the option has to be defined as the max allowed value because it need to meet all kinds of virtulization applications and need to support most of SoCs; 2) using a bigger value doesn't introduce extra memory consumption, and the help text in Kconfig isn't accurate because kvm_vpu structure isn't allocated until request of creating VCPU is sent from QEMU; 3) the main effect is that the field of vcpus[] in 'struct kvm' becomes a bit bigger(sizeof(void *) per vcpu) and need more cache lines to hold the structure, but 'struct kvm' is one generic struct, and it has worked well on other ARCHs already in this way. Also, the world switch frequecy is often low, for example, it is ~2000 when running kernel building load in VM from APM xgene KVM host, so the effect is very small, and the difference can't be observed in my test at all. Cc: Dann Frazier <dann.frazier@canonical.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-17arm: KVM: Disable virtual timer even if the guest is not using itMarc Zyngier
When running a guest with the architected timer disabled (with QEMU and the kernel_irqchip=off option, for example), it is important to make sure the timer gets turned off. Otherwise, the guest may try to enable it anyway, leading to a screaming HW interrupt. The fix is to unconditionally turn off the virtual timer on guest exit. Cc: stable@vger.kernel.org Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-16arm/arm64: KVM: vgic: Check for !irqchip_in_kernel() when mapping resourcesPavel Fedin
Until b26e5fdac43c ("arm/arm64: KVM: introduce per-VM ops"), kvm_vgic_map_resources() used to include a check on irqchip_in_kernel(), and vgic_v2_map_resources() still has it. But now vm_ops are not initialized until we call kvm_vgic_create(). Therefore kvm_vgic_map_resources() can being called without a VGIC, and we die because vm_ops.map_resources is NULL. Fixing this restores QEMU's kernel-irqchip=off option to a working state, allowing to use GIC emulation in userspace. Fixes: b26e5fdac43c ("arm/arm64: KVM: introduce per-VM ops") Cc: stable@vger.kernel.org Signed-off-by: Pavel Fedin <p.fedin@samsung.com> [maz: reworked commit message] Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-16arm: KVM: Fix incorrect device to IPA mappingMarek Majtyka
A critical bug has been found in device memory stage1 translation for VMs with more then 4GB of address space. Once vm_pgoff size is smaller then pa (which is true for LPAE case, u32 and u64 respectively) some more significant bits of pa may be lost as a shift operation is performed on u32 and later cast onto u64. Example: vm_pgoff(u32)=0x00210030, PAGE_SHIFT=12 expected pa(u64): 0x0000002010030000 produced pa(u64): 0x0000000010030000 The fix is to change the order of operations (casting first onto phys_addr_t and then shifting). Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> [maz: fixed changelog and patch formatting] Cc: stable@vger.kernel.org Signed-off-by: Marek Majtyka <marek.majtyka@tieto.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-09-04arm/arm64: KVM: Fix PSCI affinity info return value for non valid coresAlexander Spyridakis
If a guest requests the affinity info for a non-existing vCPU we need to properly return an error, instead of erroneously reporting an off state. Signed-off-by: Alexander Spyridakis <a.spyridakis@virtualopensystems.com> Signed-off-by: Alvise Rigo <a.rigo@virtualopensystems.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-08-19arm: KVM: keep arm vfp/simd exit handling consistent with arm64Mario Smarduch
After enhancing arm64 FP/SIMD exit handling, ARMv7 VFP exit branch is moved to guest trap handling. This allows us to keep exit handling flow between both architectures consistent. Signed-off-by: Mario Smarduch <m.smarduch@samsung.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-08-12KVM: arm/arm64: timer: Allow the timer to control the active stateMarc Zyngier
In order to remove the crude hack where we sneak the masked bit into the timer's control register, make use of the phys_irq_map API control the active state of the interrupt. This causes some limited changes to allow for potential error propagation. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-08-12KVM: arm/arm64: vgic: Allow dynamic mapping of physical/virtual interruptsMarc Zyngier
In order to be able to feed physical interrupts to a guest, we need to be able to establish the virtual-physical mapping between the two worlds. The mappings are kept in a set of RCU lists, indexed by virtual interrupts. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-08-12arm/arm64: KVM: Move vgic handling to a non-preemptible sectionMarc Zyngier
As we're about to introduce some serious GIC-poking to the vgic code, it is important to make sure that we're going to poke the part of the GIC that belongs to the CPU we're about to run on (otherwise, we'd end up with some unexpected interrupts firing)... Introducing a non-preemptible section in kvm_arch_vcpu_ioctl_run prevents the problem from occuring. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-08-12arm/arm64: KVM: Fix ordering of timer/GIC on guest entryMarc Zyngier
As we now inject the timer interrupt when we're about to enter the guest, it makes a lot more sense to make sure this happens before the vgic code queues the pending interrupts. Otherwise, we get the interrupt on the following exit, which is not great for latency (and leads to all kind of bizarre issues when using with active interrupts at the HW level). Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-07-21KVM: arm64: introduce vcpu->arch.debug_ptrAlex Bennée
This introduces a level of indirection for the debug registers. Instead of using the sys_regs[] directly we store registers in a structure in the vcpu. The new kvm_arm_reset_debug_ptr() sets the debug ptr to the guest context. Because we no longer give the sys_regs offset for the sys_reg_desc->reg field, but instead the index into a debug-specific struct we need to add a number of additional trap functions for each register. Also as the generic generic user-space access code no longer works we have introduced a new pair of function pointers to the sys_reg_desc structure to override the generic code when needed. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-21KVM: arm: introduce kvm_arm_init/setup/clear_debugAlex Bennée
This is a precursor for later patches which will need to do more to setup debug state before entering the hyp.S switch code. The existing functionality for setting mdcr_el2 has been moved out of hyp.S and now uses the value kept in vcpu->arch.mdcr_el2. As the assembler used to previously mask and preserve MDCR_EL2.HPMN I've had to add a mechanism to save the value of mdcr_el2 as a per-cpu variable during the initialisation code. The kernel never sets this number so we are assuming the bootcode has set up the correct value here. This also moves the conditional setting of the TDA bit from the hyp code into the C code which is currently used for the lazy debug register context switch code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-21KVM: arm: guest debug, add stub KVM_SET_GUEST_DEBUG ioctlAlex Bennée
This commit adds a stub function to support the KVM_SET_GUEST_DEBUG ioctl. Any unsupported flag will return -EINVAL. For now, only KVM_GUESTDBG_ENABLE is supported, although it won't have any effects. Signed-off-by: Alex Bennée <alex.bennee@linaro.org>. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-06-26Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-armLinus Torvalds
Pull ARM updates from Russell King: "Bigger items included in this update are: - A series of updates from Arnd for ARM randconfig build failures - Updates from Dmitry for StrongARM SA-1100 to move IRQ handling to drivers/irqchip/ - Move ARMs SP804 timer to drivers/clocksource/ - Perf updates from Mark Rutland in preparation to move the ARM perf code into drivers/ so it can be shared with ARM64. - MCPM updates from Nicolas - Add support for taking platform serial number from DT - Re-implement Keystone2 physical address space switch to conform to architecture requirements - Clean up ARMv7 LPAE code, which goes in hand with the Keystone2 changes. - L2C cleanups to avoid unlocking caches if we're prevented by the secure support to unlock. - Avoid cleaning a potentially dirty cache containing stale data on CPU initialisation - Add ARM-only entry point for secondary startup (for machines that can only call into a Thumb kernel in ARM mode). Same thing is also done for the resume entry point. - Provide arch_irqs_disabled via asm-generic - Enlarge ARMv7M vector table - Always use BFD linker for VDSO, as gold doesn't accept some of the options we need. - Fix an incorrect BSYM (for Thumb symbols) usage, and convert all BSYM compiler macros to a "badr" (for branch address). - Shut up compiler warnings provoked by our cmpxchg() implementation. - Ensure bad xchg sizes fail to link" * 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm: (75 commits) ARM: Fix build if CLKDEV_LOOKUP is not configured ARM: fix new BSYM() usage introduced via for-arm-soc branch ARM: 8383/1: nommu: avoid deprecated source register on mov ARM: 8391/1: l2c: add options to overwrite prefetching behavior ARM: 8390/1: irqflags: Get arch_irqs_disabled from asm-generic ARM: 8387/1: arm/mm/dma-mapping.c: Add arm_coherent_dma_mmap ARM: 8388/1: tcm: Don't crash when TCM banks are protected by TrustZone ARM: 8384/1: VDSO: force use of BFD linker ARM: 8385/1: VDSO: group link options ARM: cmpxchg: avoid warnings from macro-ized cmpxchg() implementations ARM: remove __bad_xchg definition ARM: 8369/1: ARMv7M: define size of vector table for Vybrid ARM: 8382/1: clocksource: make ARM_TIMER_SP804 depend on GENERIC_SCHED_CLOCK ARM: 8366/1: move Dual-Timer SP804 driver to drivers/clocksource ARM: 8365/1: introduce sp804_timer_disable and remove arm_timer.h inclusion ARM: 8364/1: fix BE32 module loading ARM: 8360/1: add secondary_startup_arm prototype in header file ARM: 8359/1: correct secondary_startup_arm mode ARM: proc-v7: sanitise and document registers around errata ARM: proc-v7: clean up MIDR access ...
2015-06-24Merge tag 'arm64-upstream' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull arm64 updates from Catalin Marinas: "Mostly refactoring/clean-up: - CPU ops and PSCI (Power State Coordination Interface) refactoring following the merging of the arm64 ACPI support, together with handling of Trusted (secure) OS instances - Using fixmap for permanent FDT mapping, removing the initial dtb placement requirements (within 512MB from the start of the kernel image). This required moving the FDT self reservation out of the memreserve processing - Idmap (1:1 mapping used for MMU on/off) handling clean-up - Removing flush_cache_all() - not safe on ARM unless the MMU is off. Last stages of CPU power down/up are handled by firmware already - "Alternatives" (run-time code patching) refactoring and support for immediate branch patching, GICv3 CPU interface access - User faults handling clean-up And some fixes: - Fix for VDSO building with broken ELF toolchains - Fix another case of init_mm.pgd usage for user mappings (during ASID roll-over broadcasting) - Fix for FPSIMD reloading after CPU hotplug - Fix for missing syscall trace exit - Workaround for .inst asm bug - Compat fix for switching the user tls tpidr_el0 register" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (42 commits) arm64: use private ratelimit state along with show_unhandled_signals arm64: show unhandled SP/PC alignment faults arm64: vdso: work-around broken ELF toolchains in Makefile arm64: kernel: rename __cpu_suspend to keep it aligned with arm arm64: compat: print compat_sp instead of sp arm64: mm: Fix freeing of the wrong memmap entries with !SPARSEMEM_VMEMMAP arm64: entry: fix context tracking for el0_sp_pc arm64: defconfig: enable memtest arm64: mm: remove reference to tlb.S from comment block arm64: Do not attempt to use init_mm in reset_context() arm64: KVM: Switch vgic save/restore to alternative_insn arm64: alternative: Introduce feature for GICv3 CPU interface arm64: psci: fix !CONFIG_HOTPLUG_CPU build warning arm64: fix bug for reloading FPSIMD state after CPU hotplug. arm64: kernel thread don't need to save fpsimd context. arm64: fix missing syscall trace exit arm64: alternative: Work around .inst assembler bugs arm64: alternative: Merge alternative-asm.h into alternative.h arm64: alternative: Allow immediate branch as alternative instruction arm64: Rework alternate sequence for ARM erratum 845719 ...
2015-06-19Merge tag 'kvm-arm-for-4.2' of ↵Paolo Bonzini
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/ARM changes for v4.2: - Proper guest time accounting - FP access fix for 32bit - The usual pile of GIC fixes - PSCI fixes - Random cleanups
2015-06-17arm/arm64: KVM: vgic: Do not save GICH_HCR / ICH_HCR_EL2Marc Zyngier
The GIC Hypervisor Configuration Register is used to enable the delivery of virtual interupts to a guest, as well as to define in which conditions maintenance interrupts are delivered to the host. This register doesn't contain any information that we need to read back (the EOIcount is utterly useless for us). So let's save ourselves some cycles, and not save it before writing zero to it. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-06-17ARM: kvm: psci: fix handling of unimplemented functionsLorenzo Pieralisi
According to the PSCI specification and the SMC/HVC calling convention, PSCI function_ids that are not implemented must return NOT_SUPPORTED as return value. Current KVM implementation takes an unhandled PSCI function_id as an error and injects an undefined instruction into the guest if PSCI implementation is called with a function_id that is not handled by the resident PSCI version (ie it is not implemented), which is not the behaviour expected by a guest when calling a PSCI function_id that is not implemented. This patch fixes this issue by returning NOT_SUPPORTED whenever the kvm PSCI call is executed for a function_id that is not implemented by the PSCI kvm layer. Cc: <stable@vger.kernel.org> # 3.18+ Cc: Christoffer Dall <christoffer.dall@linaro.org> Acked-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-06-17KVM: arm/arm64: Enable the KVM-VFIO deviceKim Phillips
The KVM-VFIO device is used by the QEMU VFIO device. It is used to record the list of in-use VFIO groups so that KVM can manipulate them. Signed-off-by: Kim Phillips <kim.phillips@linaro.org> Signed-off-by: Eric Auger <eric.auger@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-06-17arm/arm64: KVM: Properly account for guest CPU timeChristoffer Dall
Until now we have been calling kvm_guest_exit after re-enabling interrupts when we come back from the guest, but this has the unfortunate effect that CPU time accounting done in the context of timer interrupts occurring while the guest is running doesn't properly notice that the time since the last tick was spent in the guest. Inspired by the comment in the x86 code, move the kvm_guest_exit() call below the local_irq_enable() call and change __kvm_guest_exit() to kvm_guest_exit(), because we are now calling this function with interrupts enabled. We have to now explicitly disable preemption and not enable preemption before we've called kvm_guest_exit(), since otherwise we could be preempted and everything happening before we eventually get scheduled again would be accounted for as guest time. At the same time, move the trace_kvm_exit() call outside of the atomic section, since there is no reason for us to do that with interrupts disabled. Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-06-17kvm: remove one useless check extensionTiejun Chen
We already check KVM_CAP_IRQFD in generic once enable CONFIG_HAVE_KVM_IRQFD, kvm_vm_ioctl_check_extension_generic() | + switch (arg) { + ... + #ifdef CONFIG_HAVE_KVM_IRQFD + case KVM_CAP_IRQFD: + #endif + ... + return 1; + ... + } | + kvm_vm_ioctl_check_extension() So its not necessary to check this in arch again, and also fix one typo, s/emlation/emulation. Signed-off-by: Tiejun Chen <tiejun.chen@intel.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-06-17arm: KVM: force execution of HCPTR access on VM exitMarc Zyngier
On VM entry, we disable access to the VFP registers in order to perform a lazy save/restore of these registers. On VM exit, we restore access, test if we did enable them before, and save/restore the guest/host registers if necessary. In this sequence, the FPEXC register is always accessed, irrespective of the trapping configuration. If the guest didn't touch the VFP registers, then the HCPTR access has now enabled such access, but we're missing a barrier to ensure architectural execution of the new HCPTR configuration. If the HCPTR access has been delayed/reordered, the subsequent access to FPEXC will cause a trap, which we aren't prepared to handle at all. The same condition exists when trapping to enable VFP for the guest. The fix is to introduce a barrier after enabling VFP access. In the vmexit case, it can be relaxed to only takes place if the guest hasn't accessed its view of the VFP registers, making the access to FPEXC safe. The set_hcptr macro is modified to deal with both vmenter/vmexit and vmtrap operations, and now takes an optional label that is branched to when the guest hasn't touched the VFP registers. Reported-by: Vikram Sethi <vikrams@codeaurora.org> Cc: stable@kernel.org # v3.9+ Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-06-09ARM: KVM: Remove pointless void pointer castFiro Yang
No need to cast the void pointer returned by kmalloc() in arch/arm/kvm/mmu.c::kvm_alloc_stage2_pgd(). Signed-off-by: Firo Yang <firogm@gmail.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-05-28KVM: add "new" argument to kvm_arch_commit_memory_regionPaolo Bonzini
This lets the function access the new memory slot without going through kvm_memslots and id_to_memslot. It will simplify the code when more than one address space will be supported. Unfortunately, the "const"ness of the new argument must be casted away in two places. Fixing KVM to accept const struct kvm_memory_slot pointers would require modifications in pretty much all architectures, and is left for later. Reviewed-by: Radim Krcmar <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-05-27arm/arm64: kvm: add missing PSCI includeMark Rutland
We make use of the PSCI function IDs, but don't explicitly include the header which defines them. Relying on transitive header includes is fragile and will be broken as headers are refactored. This patch includes the relevant header file directly so as to avoid future breakage. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org> Tested-by: Hanjun Guo <hanjun.guo@linaro.org> Cc: Marc Zyngier <marc.zyngier@arm.com>
2015-05-26KVM: add memslots argument to kvm_arch_memslots_updatedPaolo Bonzini
Prepare for the case of multiple address spaces. Reviewed-by: Radim Krcmar <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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