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2015-09-21KVM: x86: Use adjustment in guest cycles when handling MSR_IA32_TSC_ADJUSTHaozhong Zhang
commit d7add05458084a5e3d65925764a02ca9c8202c1e upstream. When kvm_set_msr_common() handles a guest's write to MSR_IA32_TSC_ADJUST, it will calcuate an adjustment based on the data written by guest and then use it to adjust TSC offset by calling a call-back adjust_tsc_offset(). The 3rd parameter of adjust_tsc_offset() indicates whether the adjustment is in host TSC cycles or in guest TSC cycles. If SVM TSC scaling is enabled, adjust_tsc_offset() [i.e. svm_adjust_tsc_offset()] will first scale the adjustment; otherwise, it will just use the unscaled one. As the MSR write here comes from the guest, the adjustment is in guest TSC cycles. However, the current kvm_set_msr_common() uses it as a value in host TSC cycles (by using true as the 3rd parameter of adjust_tsc_offset()), which can result in an incorrect adjustment of TSC offset if SVM TSC scaling is enabled. This patch fixes this problem. Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-20kvm/fpu: Enable eager restore kvm FPU for MPXLiang Li
The MPX feature requires eager KVM FPU restore support. We have verified that MPX cannot work correctly with the current lazy KVM FPU restore mechanism. Eager KVM FPU restore should be enabled if the MPX feature is exposed to VM. Signed-off-by: Yang Zhang <yang.z.zhang@intel.com> Signed-off-by: Liang Li <liang.z.li@intel.com> [Also activate the FPU on AMD processors. - Paolo] Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-05-20kvm: fix crash in kvm_vcpu_reload_apic_access_pageAndrea Arcangeli
memslot->userfault_addr is set by the kernel with a mmap executed from the kernel but the userland can still munmap it and lead to the below oops after memslot->userfault_addr points to a host virtual address that has no vma or mapping. [ 327.538306] BUG: unable to handle kernel paging request at fffffffffffffffe [ 327.538407] IP: [<ffffffff811a7b55>] put_page+0x5/0x50 [ 327.538474] PGD 1a01067 PUD 1a03067 PMD 0 [ 327.538529] Oops: 0000 [#1] SMP [ 327.538574] Modules linked in: macvtap macvlan xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ipt_REJECT iptable_filter ip_tables tun bridge stp llc rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache xprtrdma ib_isert iscsi_target_mod ib_iser libiscsi scsi_transport_iscsi ib_srpt target_core_mod ib_srp scsi_transport_srp scsi_tgt ib_ipoib rdma_ucm ib_ucm ib_uverbs ib_umad rdma_cm ib_cm iw_cm ipmi_devintf iTCO_wdt iTCO_vendor_support intel_powerclamp coretemp dcdbas intel_rapl kvm_intel kvm crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel lrw gf128mul glue_helper ablk_helper cryptd pcspkr sb_edac edac_core ipmi_si ipmi_msghandler acpi_pad wmi acpi_power_meter lpc_ich mfd_core mei_me [ 327.539488] mei shpchp nfsd auth_rpcgss nfs_acl lockd grace sunrpc mlx4_ib ib_sa ib_mad ib_core mlx4_en vxlan ib_addr ip_tunnel xfs libcrc32c sd_mod crc_t10dif crct10dif_common crc32c_intel mgag200 syscopyarea sysfillrect sysimgblt i2c_algo_bit drm_kms_helper ttm drm ahci i2c_core libahci mlx4_core libata tg3 ptp pps_core megaraid_sas ntb dm_mirror dm_region_hash dm_log dm_mod [ 327.539956] CPU: 3 PID: 3161 Comm: qemu-kvm Not tainted 3.10.0-240.el7.userfault19.4ca4011.x86_64.debug #1 [ 327.540045] Hardware name: Dell Inc. PowerEdge R420/0CN7CM, BIOS 2.1.2 01/20/2014 [ 327.540115] task: ffff8803280ccf00 ti: ffff880317c58000 task.ti: ffff880317c58000 [ 327.540184] RIP: 0010:[<ffffffff811a7b55>] [<ffffffff811a7b55>] put_page+0x5/0x50 [ 327.540261] RSP: 0018:ffff880317c5bcf8 EFLAGS: 00010246 [ 327.540313] RAX: 00057ffffffff000 RBX: ffff880616a20000 RCX: 0000000000000000 [ 327.540379] RDX: 0000000000002014 RSI: 00057ffffffff000 RDI: fffffffffffffffe [ 327.540445] RBP: ffff880317c5bd10 R08: 0000000000000103 R09: 0000000000000000 [ 327.540511] R10: 0000000000000000 R11: 0000000000000000 R12: fffffffffffffffe [ 327.540576] R13: 0000000000000000 R14: ffff880317c5bd70 R15: ffff880317c5bd50 [ 327.540643] FS: 00007fd230b7f700(0000) GS:ffff880630800000(0000) knlGS:0000000000000000 [ 327.540717] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 327.540771] CR2: fffffffffffffffe CR3: 000000062a2c3000 CR4: 00000000000427e0 [ 327.540837] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 327.540904] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 327.540974] Stack: [ 327.541008] ffffffffa05d6d0c ffff880616a20000 0000000000000000 ffff880317c5bdc0 [ 327.541093] ffffffffa05ddaa2 0000000000000000 00000000002191bf 00000042f3feab2d [ 327.541177] 00000042f3feab2d 0000000000000002 0000000000000001 0321000000000000 [ 327.541261] Call Trace: [ 327.541321] [<ffffffffa05d6d0c>] ? kvm_vcpu_reload_apic_access_page+0x6c/0x80 [kvm] [ 327.543615] [<ffffffffa05ddaa2>] vcpu_enter_guest+0x3f2/0x10f0 [kvm] [ 327.545918] [<ffffffffa05e2f10>] kvm_arch_vcpu_ioctl_run+0x2b0/0x5a0 [kvm] [ 327.548211] [<ffffffffa05e2d02>] ? kvm_arch_vcpu_ioctl_run+0xa2/0x5a0 [kvm] [ 327.550500] [<ffffffffa05ca845>] kvm_vcpu_ioctl+0x2b5/0x680 [kvm] [ 327.552768] [<ffffffff810b8d12>] ? creds_are_invalid.part.1+0x12/0x50 [ 327.555069] [<ffffffff810b8d71>] ? creds_are_invalid+0x21/0x30 [ 327.557373] [<ffffffff812d6066>] ? inode_has_perm.isra.49.constprop.65+0x26/0x80 [ 327.559663] [<ffffffff8122d985>] do_vfs_ioctl+0x305/0x530 [ 327.561917] [<ffffffff8122dc51>] SyS_ioctl+0xa1/0xc0 [ 327.564185] [<ffffffff816de829>] system_call_fastpath+0x16/0x1b [ 327.566480] Code: 0b 31 f6 4c 89 e7 e8 4b 7f ff ff 0f 0b e8 24 fd ff ff e9 a9 fd ff ff 66 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 66 66 66 66 90 <48> f7 07 00 c0 00 00 55 48 89 e5 75 2a 8b 47 1c 85 c0 74 1e f0 Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-05-11KVM: MMU: fix SMAP virtualizationXiao Guangrong
KVM may turn a user page to a kernel page when kernel writes a readonly user page if CR0.WP = 1. This shadow page entry will be reused after SMAP is enabled so that kernel is allowed to access this user page Fix it by setting SMAP && !CR0.WP into shadow page's role and reset mmu once CR4.SMAP is updated Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-04-27kvm: x86: fix kvmclock update protocolRadim Krčmář
The kvmclock spec says that the host will increment a version field to an odd number, then update stuff, then increment it to an even number. The host is buggy and doesn't do this, and the result is observable when one vcpu reads another vcpu's kvmclock data. There's no good way for a guest kernel to keep its vdso from reading a different vcpu's kvmclock data, but we don't need to care about changing VCPUs as long as we read a consistent data from kvmclock. (VCPU can change outside of this loop too, so it doesn't matter if we return a value not fit for this VCPU.) Based on a patch by Radim Krčmář. Reviewed-by: Radim Krčmář <rkrcmar@redhat.com> Acked-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-04-14KVM: x86: Fix MSR_IA32_BNDCFGS in msrs_to_saveNadav Amit
kvm_init_msr_list is currently called before hardware_setup. As a result, vmx_mpx_supported always returns false when kvm_init_msr_list checks whether to save MSR_IA32_BNDCFGS. Move kvm_init_msr_list after vmx_hardware_setup is called to fix this issue. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Message-Id: <1428864435-4732-1-git-send-email-namit@cs.technion.ac.il> Cc: stable@vger.kernel.org # 3.15+ Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-04-13Merge branch 'timers-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer updates from Ingo Molnar: "The main changes in this cycle were: - clockevents state machine cleanups and enhancements (Viresh Kumar) - clockevents broadcast notifier horror to state machine conversion and related cleanups (Thomas Gleixner, Rafael J Wysocki) - clocksource and timekeeping core updates (John Stultz) - clocksource driver updates and fixes (Ben Dooks, Dmitry Osipenko, Hans de Goede, Laurent Pinchart, Maxime Ripard, Xunlei Pang) - y2038 fixes (Xunlei Pang, John Stultz) - NMI-safe ktime_get_raw_fast() and general refactoring of the clock code, in preparation to perf's per event clock ID support (Peter Zijlstra) - generic sched/clock fixes, optimizations and cleanups (Daniel Thompson) - clockevents cpu_down() race fix (Preeti U Murthy)" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (94 commits) timers/PM: Drop unnecessary braces from tick_freeze() timers/PM: Fix up tick_unfreeze() timekeeping: Get rid of stale comment clockevents: Cleanup dead cpu explicitely clockevents: Make tick handover explicit clockevents: Remove broadcast oneshot control leftovers sched/idle: Use explicit broadcast oneshot control function ARM: Tegra: Use explicit broadcast oneshot control function ARM: OMAP: Use explicit broadcast oneshot control function intel_idle: Use explicit broadcast oneshot control function ACPI/idle: Use explicit broadcast control function ACPI/PAD: Use explicit broadcast oneshot control function x86/amd/idle, clockevents: Use explicit broadcast oneshot control functions clockevents: Provide explicit broadcast oneshot control functions clockevents: Remove the broadcast control leftovers ARM: OMAP: Use explicit broadcast control function intel_idle: Use explicit broadcast control function cpuidle: Use explicit broadcast control function ACPI/processor: Use explicit broadcast control function ACPI/PAD: Use explicit broadcast control function ...
2015-04-13Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull KVM updates from Paolo Bonzini: "First batch of KVM changes for 4.1 The most interesting bit here is irqfd/ioeventfd support for ARM and ARM64. Summary: ARM/ARM64: fixes for live migration, irqfd and ioeventfd support (enabling vhost, too), page aging s390: interrupt handling rework, allowing to inject all local interrupts via new ioctl and to get/set the full local irq state for migration and introspection. New ioctls to access memory by virtual address, and to get/set the guest storage keys. SIMD support. MIPS: FPU and MIPS SIMD Architecture (MSA) support. Includes some patches from Ralf Baechle's MIPS tree. x86: bugfixes (notably for pvclock, the others are small) and cleanups. Another small latency improvement for the TSC deadline timer" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (146 commits) KVM: use slowpath for cross page cached accesses kvm: mmu: lazy collapse small sptes into large sptes KVM: x86: Clear CR2 on VCPU reset KVM: x86: DR0-DR3 are not clear on reset KVM: x86: BSP in MSR_IA32_APICBASE is writable KVM: x86: simplify kvm_apic_map KVM: x86: avoid logical_map when it is invalid KVM: x86: fix mixed APIC mode broadcast KVM: x86: use MDA for interrupt matching kvm/ppc/mpic: drop unused IRQ_testbit KVM: nVMX: remove unnecessary double caching of MAXPHYADDR KVM: nVMX: checks for address bits beyond MAXPHYADDR on VM-entry KVM: x86: cache maxphyaddr CPUID leaf in struct kvm_vcpu KVM: vmx: pass error code with internal error #2 x86: vdso: fix pvclock races with task migration KVM: remove kvm_read_hva and kvm_read_hva_atomic KVM: x86: optimize delivery of TSC deadline timer interrupt KVM: x86: extract blocking logic from __vcpu_run kvm: x86: fix x86 eflags fixed bit KVM: s390: migrate vcpu interrupt state ...
2015-04-08kvm: mmu: lazy collapse small sptes into large sptesWanpeng Li
Dirty logging tracks sptes in 4k granularity, meaning that large sptes have to be split. If live migration is successful, the guest in the source machine will be destroyed and large sptes will be created in the destination. However, the guest continues to run in the source machine (for example if live migration fails), small sptes will remain around and cause bad performance. This patch introduce lazy collapsing of small sptes into large sptes. The rmap will be scanned in ioctl context when dirty logging is stopped, dropping those sptes which can be collapsed into a single large-page spte. Later page faults will create the large-page sptes. Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com> Message-Id: <1428046825-6905-1-git-send-email-wanpeng.li@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-04-08KVM: x86: Clear CR2 on VCPU resetNadav Amit
CR2 is not cleared as it should after reset. See Intel SDM table named "IA-32 Processor States Following Power-up, Reset, or INIT". Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Message-Id: <1427933438-12782-5-git-send-email-namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-04-08KVM: x86: DR0-DR3 are not clear on resetNadav Amit
DR0-DR3 are not cleared as they should during reset and when they are set from userspace. It appears to be caused by c77fb5fe6f03 ("KVM: x86: Allow the guest to run with dirty debug registers"). Force their reload on these situations. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Message-Id: <1427933438-12782-4-git-send-email-namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-04-08KVM: x86: BSP in MSR_IA32_APICBASE is writableNadav Amit
After reset, the CPU can change the BSP, which will be used upon INIT. Reset should return the BSP which QEMU asked for, and therefore handled accordingly. To quote: "If the MP protocol has completed and a BSP is chosen, subsequent INITs (either to a specific processor or system wide) do not cause the MP protocol to be repeated." [Intel SDM 8.4.2: MP Initialization Protocol Requirements and Restrictions] Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Message-Id: <1427933438-12782-3-git-send-email-namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-04-08KVM: x86: cache maxphyaddr CPUID leaf in struct kvm_vcpuEugene Korenevsky
cpuid_maxphyaddr(), which performs lot of memory accesses is called extensively across KVM, especially in nVMX code. This patch adds a cached value of maxphyaddr to vcpu.arch to reduce the pressure onto CPU cache and simplify the code of cpuid_maxphyaddr() callers. The cached value is initialized in kvm_arch_vcpu_init() and reloaded every time CPUID is updated by usermode. It is obvious that these reloads occur infrequently. Signed-off-by: Eugene Korenevsky <ekorenevsky@gmail.com> Message-Id: <20150329205612.GA1223@gnote> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-04-08KVM: x86: optimize delivery of TSC deadline timer interruptPaolo Bonzini
The newly-added tracepoint shows the following results on the tscdeadline_latency test: qemu-kvm-8387 [002] 6425.558974: kvm_vcpu_wakeup: poll time 10407 ns qemu-kvm-8387 [002] 6425.558984: kvm_vcpu_wakeup: poll time 0 ns qemu-kvm-8387 [002] 6425.561242: kvm_vcpu_wakeup: poll time 10477 ns qemu-kvm-8387 [002] 6425.561251: kvm_vcpu_wakeup: poll time 0 ns and so on. This is because we need to go through kvm_vcpu_block again after the timer IRQ is injected. Avoid it by polling once before entering kvm_vcpu_block. On my machine (Xeon E5 Sandy Bridge) this removes about 500 cycles (7%) from the latency of the TSC deadline timer. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-04-08KVM: x86: extract blocking logic from __vcpu_runPaolo Bonzini
Rename the old __vcpu_run to vcpu_run, and extract part of it to a new function vcpu_block. The next patch will add a new condition in vcpu_block, avoid extra indentation. Reviewed-by: David Matlack <dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-04-07Merge tag 'kvm-arm-for-4.1' of ↵Paolo Bonzini
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into 'kvm-next' KVM/ARM changes for v4.1: - fixes for live migration - irqfd support - kvm-io-bus & vgic rework to enable ioeventfd - page ageing for stage-2 translation - various cleanups
2015-03-31Merge tag 'v4.0-rc6' into timers/core, before applying new patchesIngo Molnar
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-27time: Rename timekeeper::tkr to timekeeper::tkr_monoPeter Zijlstra
In preparation of adding another tkr field, rename this one to tkr_mono. Also rename tk_read_base::base_mono to tk_read_base::base, since the structure is not specific to CLOCK_MONOTONIC and the mono name got added to the tk_read_base instance. Lots of trivial churn. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: John Stultz <john.stultz@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150319093400.344679419@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-26KVM: Redesign kvm_io_bus_ API to pass VCPU structure to the callbacks.Nikolay Nikolaev
This is needed in e.g. ARM vGIC emulation, where the MMIO handling depends on the VCPU that does the access. Signed-off-by: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com> Signed-off-by: Andre Przywara <andre.przywara@arm.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-03-17KVM: x86: For the symbols used locally only should be static typeXiubo Li
This patch fix the following sparse warnings: for arch/x86/kvm/x86.c: warning: symbol 'emulator_read_write' was not declared. Should it be static? warning: symbol 'emulator_write_emulated' was not declared. Should it be static? warning: symbol 'emulator_get_dr' was not declared. Should it be static? warning: symbol 'emulator_set_dr' was not declared. Should it be static? for arch/x86/kvm/pmu.c: warning: symbol 'fixed_pmc_events' was not declared. Should it be static? Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2015-03-17KVM: x86: Avoid using plain integer as NULL pointer warningXiubo Li
This patch fix the following sparse warning: for file arch/x86/kvm/x86.c: warning: Using plain integer as NULL pointer Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2015-03-10kvm: move advertising of KVM_CAP_IRQFD to common codePaolo Bonzini
POWER supports irqfds but forgot to advertise them. Some userspace does not check for the capability, but others check it---thus they work on x86 and s390 but not POWER. To avoid that other architectures in the future make the same mistake, let common code handle KVM_CAP_IRQFD the same way as KVM_CAP_IRQFD_RESAMPLE. Reported-and-tested-by: Greg Kurz <gkurz@linux.vnet.ibm.com> Cc: stable@vger.kernel.org Fixes: 297e21053a52f060944e9f0de4c64fad9bcd72fc Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2015-03-10kvm: x86: make kvm_emulate_* consistantJoel Schopp
Currently kvm_emulate() skips the instruction but kvm_emulate_* sometimes don't. The end reult is the caller ends up doing the skip themselves. Let's make them consistant. Signed-off-by: Joel Schopp <joel.schopp@amd.com> Reviewed-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2015-03-10KVM: Get rid of kvm_kvfree()Thomas Huth
kvm_kvfree() provides exactly the same functionality as the new common kvfree() function - so let's simply replace the kvm function with the common function. Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2015-02-06kvm: add halt_poll_ns module parameterPaolo Bonzini
This patch introduces a new module parameter for the KVM module; when it is present, KVM attempts a bit of polling on every HLT before scheduling itself out via kvm_vcpu_block. This parameter helps a lot for latency-bound workloads---in particular I tested it with O_DSYNC writes with a battery-backed disk in the host. In this case, writes are fast (because the data doesn't have to go all the way to the platters) but they cannot be merged by either the host or the guest. KVM's performance here is usually around 30% of bare metal, or 50% if you use cache=directsync or cache=writethrough (these parameters avoid that the guest sends pointless flush requests, and at the same time they are not slow because of the battery-backed cache). The bad performance happens because on every halt the host CPU decides to halt itself too. When the interrupt comes, the vCPU thread is then migrated to a new physical CPU, and in general the latency is horrible because the vCPU thread has to be scheduled back in. With this patch performance reaches 60-65% of bare metal and, more important, 99% of what you get if you use idle=poll in the guest. This means that the tunable gets rid of this particular bottleneck, and more work can be done to improve performance in the kernel or QEMU. Of course there is some price to pay; every time an otherwise idle vCPUs is interrupted by an interrupt, it will poll unnecessarily and thus impose a little load on the host. The above results were obtained with a mostly random value of the parameter (500000), and the load was around 1.5-2.5% CPU usage on one of the host's core for each idle guest vCPU. The patch also adds a new stat, /sys/kernel/debug/kvm/halt_successful_poll, that can be used to tune the parameter. It counts how many HLT instructions received an interrupt during the polling period; each successful poll avoids that Linux schedules the VCPU thread out and back in, and may also avoid a likely trip to C1 and back for the physical CPU. While the VM is idle, a Linux 4 VCPU VM halts around 10 times per second. Of these halts, almost all are failed polls. During the benchmark, instead, basically all halts end within the polling period, except a more or less constant stream of 50 per second coming from vCPUs that are not running the benchmark. The wasted time is thus very low. Things may be slightly different for Windows VMs, which have a ~10 ms timer tick. The effect is also visible on Marcelo's recently-introduced latency test for the TSC deadline timer. Though of course a non-RT kernel has awful latency bounds, the latency of the timer is around 8000-10000 clock cycles compared to 20000-120000 without setting halt_poll_ns. For the TSC deadline timer, thus, the effect is both a smaller average latency and a smaller variance. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-01-30KVM: VMX: Add PML support in VMXKai Huang
This patch adds PML support in VMX. A new module parameter 'enable_pml' is added to allow user to enable/disable it manually. Signed-off-by: Kai Huang <kai.huang@linux.intel.com> Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-01-29KVM: x86: Add new dirty logging kvm_x86_ops for PMLKai Huang
This patch adds new kvm_x86_ops dirty logging hooks to enable/disable dirty logging for particular memory slot, and to flush potentially logged dirty GPAs before reporting slot->dirty_bitmap to userspace. kvm x86 common code calls these hooks when they are available so PML logic can be hidden to VMX specific. SVM won't be impacted as these hooks remain NULL there. Signed-off-by: Kai Huang <kai.huang@linux.intel.com> Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-01-29KVM: x86: Change parameter of kvm_mmu_slot_remove_write_accessKai Huang
This patch changes the second parameter of kvm_mmu_slot_remove_write_access from 'slot id' to 'struct kvm_memory_slot *' to align with kvm_x86_ops dirty logging hooks, which will be introduced in further patch. Better way is to change second parameter of kvm_arch_commit_memory_region from 'struct kvm_userspace_memory_region *' to 'struct kvm_memory_slot * new', but it requires changes on other non-x86 ARCH too, so avoid it now. Signed-off-by: Kai Huang <kai.huang@linux.intel.com> Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-01-26KVM: x86: 32-bit wraparound read/write not emulated correctlyNadav Amit
If we got a wraparound of 32-bit operand, and the limit is 0xffffffff, read and writes should be successful. It just needs to be done in two segments. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-01-26KVM: x86: IRET emulation does not clear NMI maskingNadav Amit
The IRET instruction should clear NMI masking, but the current implementation does not do so. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-01-23Merge tag 'kvm-s390-next-20150122' of ↵Paolo Bonzini
git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into kvm-next KVM: s390: fixes and features for kvm/next (3.20) 1. Generic - sparse warning (make function static) - optimize locking - bugfixes for interrupt injection - fix MVPG addressing modes 2. hrtimer/wakeup fun A recent change can cause KVM hangs if adjtime is used in the host. The hrtimer might wake up too early or too late. Too early is fatal as vcpu_block will see that the wakeup condition is not met and sleep again. This CPU might never wake up again. This series addresses this problem. adjclock slowing down the host clock will result in too late wakeups. This will require more work. In addition to that we also change the hrtimer from REALTIME to MONOTONIC to avoid similar problems with timedatectl set-time. 3. sigp rework We will move all "slow" sigps to QEMU (protected with a capability that can be enabled) to avoid several races between concurrent SIGP orders. 4. Optimize the shadow page table Provide an interface to announce the maximum guest size. The kernel will use that to make the pagetable 2,3,4 (or theoretically) 5 levels. 5. Provide an interface to set the guest TOD We now use two vm attributes instead of two oneregs, as oneregs are vcpu ioctl and we don't want to call them from other threads. 6. Protected key functions The real HMC allows to enable/disable protected key CPACF functions. Lets provide an implementation + an interface for QEMU to activate this the protected key instructions.
2015-01-23Merge tag 'kvm-arm-for-3.20' of ↵Paolo Bonzini
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into kvm-next KVM/ARM changes for v3.20 including GICv3 emulation, dirty page logging, added trace symbols, and adding an explicit VGIC init device control IOCTL. Conflicts: arch/arm64/include/asm/kvm_arm.h arch/arm64/kvm/handle_exit.c
2015-01-23KVM: remove unneeded return value of vcpu_postcreateDominik Dingel
The return value of kvm_arch_vcpu_postcreate is not checked in its caller. This is okay, because only x86 provides vcpu_postcreate right now and it could only fail if vcpu_load failed. But that is not possible during KVM_CREATE_VCPU (kvm_arch_vcpu_load is void, too), so just get rid of the unchecked return value. Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2015-01-20KVM: x86: workaround SuSE's 2.6.16 pvclock vs masterclock issueMarcelo Tosatti
SuSE's 2.6.16 kernel fails to boot if the delta between tsc_timestamp and rdtsc is larger than a given threshold: * If we get more than the below threshold into the future, we rerequest * the real time from the host again which has only little offset then * that we need to adjust using the TSC. * * For now that threshold is 1/5th of a jiffie. That should be good * enough accuracy for completely broken systems, but also give us swing * to not call out to the host all the time. */ #define PVCLOCK_DELTA_MAX ((1000000000ULL / HZ) / 5) Disable masterclock support (which increases said delta) in case the boot vcpu does not use MSR_KVM_SYSTEM_TIME_NEW. Upstreams kernels which support pvclock vsyscalls (and therefore make use of PVCLOCK_STABLE_BIT) use MSR_KVM_SYSTEM_TIME_NEW. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-01-20KVM: fix "Should it be static?" warnings from sparseFengguang Wu
arch/x86/kvm/x86.c:495:5: sparse: symbol 'kvm_read_nested_guest_page' was not declared. Should it be static? arch/x86/kvm/x86.c:646:5: sparse: symbol '__kvm_set_xcr' was not declared. Should it be static? arch/x86/kvm/x86.c:1183:15: sparse: symbol 'max_tsc_khz' was not declared. Should it be static? arch/x86/kvm/x86.c:1237:6: sparse: symbol 'kvm_track_tsc_matching' was not declared. Should it be static? Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-01-16KVM: x86: switch to kvm_get_dirty_log_protectPaolo Bonzini
We now have a generic function that does most of the work of kvm_vm_ioctl_get_dirty_log, now use it. Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Mario Smarduch <m.smarduch@samsung.com>
2015-01-09KVM: x86: allow TSC deadline timer on all hostsRadim Krčmář
Emulation does not utilize the feature. Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-01-08kvm: x86: Remove kvm_make_request from lapic.cNicholas Krause
Adds a function kvm_vcpu_set_pending_timer instead of calling kvm_make_request in lapic.c. Signed-off-by: Nicholas Krause <xerofoify@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-01-08KVM: x86: add option to advance tscdeadline hrtimer expirationMarcelo Tosatti
For the hrtimer which emulates the tscdeadline timer in the guest, add an option to advance expiration, and busy spin on VM-entry waiting for the actual expiration time to elapse. This allows achieving low latencies in cyclictest (or any scenario which requires strict timing regarding timer expiration). Reduces average cyclictest latency from 12us to 8us on Core i5 desktop. Note: this option requires tuning to find the appropriate value for a particular hardware/guest combination. One method is to measure the average delay between apic_timer_fn and VM-entry. Another method is to start with 1000ns, and increase the value in say 500ns increments until avg cyclictest numbers stop decreasing. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-01-08KVM: nVMX: Add nested msr load/restore algorithmWincy Van
Several hypervisors need MSR auto load/restore feature. We read MSRs from VM-entry MSR load area which specified by L1, and load them via kvm_set_msr in the nested entry. When nested exit occurs, we get MSRs via kvm_get_msr, writing them to L1`s MSR store area. After this, we read MSRs from VM-exit MSR load area, and load them via kvm_set_msr. Signed-off-by: Wincy Van <fanwenyi0529@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-12-05KVM: x86: support XSAVES usage in the hostPaolo Bonzini
Userspace is expecting non-compacted format for KVM_GET_XSAVE, but struct xsave_struct might be using the compacted format. Convert in order to preserve userspace ABI. Likewise, userspace is passing non-compacted format for KVM_SET_XSAVE but the kernel will pass it to XRSTORS, and we need to convert back. Fixes: f31a9f7c71691569359fa7fb8b0acaa44bce0324 Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: stable@vger.kernel.org Cc: H. Peter Anvin <hpa@linux.intel.com> Tested-by: Nadav Amit <namit@cs.technion.ac.il> Reviewed-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-24kvm: x86: avoid warning about potential shift wrapping bugPaolo Bonzini
cs.base is declared as a __u64 variable and vector is a u32 so this causes a static checker warning. The user indeed can set "sipi_vector" to any u32 value in kvm_vcpu_ioctl_x86_set_vcpu_events(), but the value should really have 8-bit precision only. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-24KVM: x86: move device assignment out of kvm_host.hPaolo Bonzini
Create a new header, and hide the device assignment functions there. Move struct kvm_assigned_dev_kernel to assigned-dev.c by modifying arch/x86/kvm/iommu.c to take a PCI device struct. Based on a patch by Radim Krcmar <rkrcmark@redhat.com>. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-23kvm: x86: move assigned-dev.c and iommu.c to arch/x86/Radim Krčmář
Now that ia64 is gone, we can hide deprecated device assignment in x86. Notable changes: - kvm_vm_ioctl_assigned_device() was moved to x86/kvm_arch_vm_ioctl() The easy parts were removed from generic kvm code, remaining - kvm_iommu_(un)map_pages() would require new code to be moved - struct kvm_assigned_dev_kernel depends on struct kvm_irq_ack_notifier Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-21kvm: x86: move ioapic.c and irq_comm.c back to arch/x86/Paolo Bonzini
ia64 does not need them anymore. Ack notifiers become x86-specific too. Suggested-by: Gleb Natapov <gleb@kernel.org> Reviewed-by: Radim Krcmar <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-13kvm: svm: move WARN_ON in svm_adjust_tsc_offsetChris J Arges
When running the tsc_adjust kvm-unit-test on an AMD processor with the IA32_TSC_ADJUST feature enabled, the WARN_ON in svm_adjust_tsc_offset can be triggered. This WARN_ON checks for a negative adjustment in case __scale_tsc is called; however it may trigger unnecessary warnings. This patch moves the WARN_ON to trigger only if __scale_tsc will actually be called from svm_adjust_tsc_offset. In addition make adj in kvm_set_msr_common s64 since this can have signed values. Signed-off-by: Chris J Arges <chris.j.arges@canonical.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-10KVM: x86: fix warning on 32-bit compilationPaolo Bonzini
PCIDs are only supported in 64-bit mode. No need to clear bit 63 of CR3 unless the host is 64-bit. Reported by Fengguang Wu's autobuilder. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-08kvm: x86: add trace event for pvclock updatesDavid Matlack
The new trace event records: * the id of vcpu being updated * the pvclock_vcpu_time_info struct being written to guest memory This is useful for debugging pvclock bugs, such as the bug fixed by "[PATCH] kvm: x86: Fix kvm clock versioning.". Signed-off-by: David Matlack <dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-08kvm: x86: Fix kvm clock versioning.Owen Hofmann
kvm updates the version number for the guest paravirt clock structure by incrementing the version of its private copy. It does not read the guest version, so will write version = 2 in the first update for every new VM, including after restoring a saved state. If guest state is saved during reading the clock, it could read and accept struct fields and guest TSC from two different updates. This changes the code to increment the guest version and write it back. Signed-off-by: Owen Hofmann <osh@google.com> Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-08KVM: x86: update masterclock values on TSC writesMarcelo Tosatti
When the guest writes to the TSC, the masterclock TSC copy must be updated as well along with the TSC_OFFSET update, otherwise a negative tsc_timestamp is calculated at kvm_guest_time_update. Once "if (!vcpus_matched && ka->use_master_clock)" is simplified to "if (ka->use_master_clock)", the corresponding "if (!ka->use_master_clock)" becomes redundant, so remove the do_request boolean and collapse everything into a single condition. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
generated by cgit v1.2.3 (git 2.0.4) at 2025-08-12 03:25:04 +0000