linux-toradex.git/include/kvm, branch toradex_5.15-2.2.x-imx Linux kernel for Apalis and Colibri modules KVM: arm64: vgic-v4: Make the doorbell request robust w.r.t preemption 2024-07-05T07:14:51+00:00 Marc Zyngier maz@kernel.org 2023-07-13T07:06:57+00:00 468ef1530f0fae5176ebf98f1a7a4cdea7752e3e commit b321c31c9b7b309dcde5e8854b741c8e6a9a05f0 upstream. Xiang reports that VMs occasionally fail to boot on GICv4.1 systems when running a preemptible kernel, as it is possible that a vCPU is blocked without requesting a doorbell interrupt. The issue is that any preemption that occurs between vgic_v4_put() and schedule() on the block path will mark the vPE as nonresident and *not* request a doorbell irq. This occurs because when the vcpu thread is resumed on its way to block, vcpu_load() will make the vPE resident again. Once the vcpu actually blocks, we don't request a doorbell anymore, and the vcpu won't be woken up on interrupt delivery. Fix it by tracking that we're entering WFI, and key the doorbell request on that flag. This allows us not to make the vPE resident when going through a preempt/schedule cycle, meaning we don't lose any state. Cc: stable@vger.kernel.org Fixes: 8e01d9a396e6 ("KVM: arm64: vgic-v4: Move the GICv4 residency flow to be driven by vcpu_load/put") Reported-by: Xiang Chen <chenxiang66@hisilicon.com> Suggested-by: Zenghui Yu <yuzenghui@huawei.com> Tested-by: Xiang Chen <chenxiang66@hisilicon.com> Co-developed-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Marc Zyngier <maz@kernel.org> Acked-by: Zenghui Yu <yuzenghui@huawei.com> Link: https://lore.kernel.org/r/20230713070657.3873244-1-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev> [ modified to wrangle the vCPU flags directly instead of going through the flag helper macros as they have not yet been introduced. Also doing the flag wranging in the kvm_arch_vcpu_{un}blocking() hooks as the introduction of kvm_vcpu_wfi has not yet happened. See: 6109c5a6ab7f ("KVM: arm64: Move vGIC v4 handling for WFI out arch callback hook") ] Signed-off-by: James Gowans <jgowans@amazon.com> Acked-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit b321c31c9b7b309dcde5e8854b741c8e6a9a05f0 upstream.

Xiang reports that VMs occasionally fail to boot on GICv4.1 systems when
running a preemptible kernel, as it is possible that a vCPU is blocked
without requesting a doorbell interrupt.

The issue is that any preemption that occurs between vgic_v4_put() and
schedule() on the block path will mark the vPE as nonresident and *not*
request a doorbell irq. This occurs because when the vcpu thread is
resumed on its way to block, vcpu_load() will make the vPE resident
again. Once the vcpu actually blocks, we don't request a doorbell
anymore, and the vcpu won't be woken up on interrupt delivery.

Fix it by tracking that we're entering WFI, and key the doorbell
request on that flag. This allows us not to make the vPE resident
when going through a preempt/schedule cycle, meaning we don't lose
any state.

Cc: stable@vger.kernel.org
Fixes: 8e01d9a396e6 ("KVM: arm64: vgic-v4: Move the GICv4 residency flow to be driven by vcpu_load/put")
Reported-by: Xiang Chen <chenxiang66@hisilicon.com>
Suggested-by: Zenghui Yu <yuzenghui@huawei.com>
Tested-by: Xiang Chen <chenxiang66@hisilicon.com>
Co-developed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Zenghui Yu <yuzenghui@huawei.com>
Link: https://lore.kernel.org/r/20230713070657.3873244-1-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
[ modified to wrangle the vCPU flags directly instead of going through
  the flag helper macros as they have not yet been introduced. Also doing
  the flag wranging in the kvm_arch_vcpu_{un}blocking() hooks as the
  introduction of kvm_vcpu_wfi has not yet happened. See:
  6109c5a6ab7f ("KVM: arm64: Move vGIC v4 handling for WFI out arch callback hook") ]
Signed-off-by: James Gowans <jgowans@amazon.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
KVM: arm64: Fix PMU probe ordering 2021-09-20T11:43:34+00:00 Marc Zyngier maz@kernel.org 2021-09-19T13:09:49+00:00 e840f42a49925707fca90e6c7a4095118fdb8c4d Russell reported that since 5.13, KVM's probing of the PMU has started to fail on his HW. As it turns out, there is an implicit ordering dependency between the architectural PMU probing code and and KVM's own probing. If, due to probe ordering reasons, KVM probes before the PMU driver, it will fail to detect the PMU and prevent it from being advertised to guests as well as the VMM. Obviously, this is one probing too many, and we should be able to deal with any ordering. Add a callback from the PMU code into KVM to advertise the registration of a host CPU PMU, allowing for any probing order. Fixes: 5421db1be3b1 ("KVM: arm64: Divorce the perf code from oprofile helpers") Reported-by: "Russell King (Oracle)" <linux@armlinux.org.uk> Tested-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/YUYRKVflRtUytzy5@shell.armlinux.org.uk Cc: stable@vger.kernel.org 
Russell reported that since 5.13, KVM's probing of the PMU has
started to fail on his HW. As it turns out, there is an implicit
ordering dependency between the architectural PMU probing code and
and KVM's own probing. If, due to probe ordering reasons, KVM probes
before the PMU driver, it will fail to detect the PMU and prevent it
from being advertised to guests as well as the VMM.

Obviously, this is one probing too many, and we should be able to
deal with any ordering.

Add a callback from the PMU code into KVM to advertise the registration
of a host CPU PMU, allowing for any probing order.

Fixes: 5421db1be3b1 ("KVM: arm64: Divorce the perf code from oprofile helpers")
Reported-by: "Russell King (Oracle)" <linux@armlinux.org.uk>
Tested-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/YUYRKVflRtUytzy5@shell.armlinux.org.uk
Cc: stable@vger.kernel.org
KVM: arm64: vgic: Implement SW-driven deactivation 2021-06-01T09:46:00+00:00 Marc Zyngier maz@kernel.org 2021-03-15T13:11:58+00:00 354920e79441c8a53ac73008b06d3b70ed06eb34 In order to deal with these systems that do not offer HW-based deactivation of interrupts, let implement a SW-based approach: - When the irq is queued into a LR, treat it as a pure virtual interrupt and set the EOI flag in the LR. - When the interrupt state is read back from the LR, force a deactivation when the state is invalid (neither active nor pending) Interrupts requiring such treatment get the VGIC_SW_RESAMPLE flag. Signed-off-by: Marc Zyngier <maz@kernel.org> 
In order to deal with these systems that do not offer HW-based
deactivation of interrupts, let implement a SW-based approach:

- When the irq is queued into a LR, treat it as a pure virtual
  interrupt and set the EOI flag in the LR.

- When the interrupt state is read back from the LR, force a
  deactivation when the state is invalid (neither active nor
  pending)

Interrupts requiring such treatment get the VGIC_SW_RESAMPLE flag.

Signed-off-by: Marc Zyngier <maz@kernel.org>
KVM: arm64: vgic: move irq->get_input_level into an ops structure 2021-06-01T09:45:59+00:00 Marc Zyngier maz@kernel.org 2021-03-01T17:39:39+00:00 db75f1a33f82ad332b6e139c5960e01999969d2c We already have the option to attach a callback to an interrupt to retrieve its pending state. As we are planning to expand this facility, move this callback into its own data structure. This will limit the size of individual interrupts as the ops structures can be shared across multiple interrupts. Signed-off-by: Marc Zyngier <maz@kernel.org> 
We already have the option to attach a callback to an interrupt
to retrieve its pending state. As we are planning to expand this
facility, move this callback into its own data structure.

This will limit the size of individual interrupts as the ops
structures can be shared across multiple interrupts.

Signed-off-by: Marc Zyngier <maz@kernel.org>
KVM: arm64: vgic: Let an interrupt controller advertise lack of HW deactivation 2021-06-01T09:45:59+00:00 Marc Zyngier maz@kernel.org 2021-03-15T21:56:47+00:00 f6c3e24fb721dda247f6691c809d6e6c413f22c7 The vGIC, as architected by ARM, allows a virtual interrupt to trigger the deactivation of a physical interrupt. This allows the following interrupt to be delivered without requiring an exit. However, some implementations have choosen not to implement this, meaning that we will need some unsavoury workarounds to deal with this. On detecting such a case, taint the kernel and spit a nastygram. We'll deal with this in later patches. Signed-off-by: Marc Zyngier <maz@kernel.org> 
The vGIC, as architected by ARM, allows a virtual interrupt to
trigger the deactivation of a physical interrupt. This allows
the following interrupt to be delivered without requiring an exit.

However, some implementations have choosen not to implement this,
meaning that we will need some unsavoury workarounds to deal with this.

On detecting such a case, taint the kernel and spit a nastygram.
We'll deal with this in later patches.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Merge branch 'kvm-arm64/kill_oprofile_dependency' into kvmarm-master/next 2021-04-22T12:41:49+00:00 Marc Zyngier maz@kernel.org 2021-04-22T12:41:49+00:00 9a8aae605b80fc0a830cdce747eed48e11acc067 Signed-off-by: Marc Zyngier <maz@kernel.org> 
Signed-off-by: Marc Zyngier <maz@kernel.org>
KVM: arm64: Divorce the perf code from oprofile helpers 2021-04-22T12:32:39+00:00 Marc Zyngier maz@kernel.org 2021-04-14T13:44:05+00:00 5421db1be3b11c5e469cce3760d5c8a013a90f2c KVM/arm64 is the sole user of perf_num_counters(), and really could do without it. Stop using the obsolete API by relying on the existing probing code. Signed-off-by: Marc Zyngier <maz@kernel.org> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20210414134409.1266357-2-maz@kernel.org 
KVM/arm64 is the sole user of perf_num_counters(), and really
could do without it. Stop using the obsolete API by relying on
the existing probing code.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210414134409.1266357-2-maz@kernel.org
KVM: arm64: vgic-v3: Expose GICR_TYPER.Last for userspace 2021-04-06T13:51:38+00:00 Eric Auger eric.auger@redhat.com 2021-04-05T16:39:40+00:00 28e9d4bce3be9b8fec6c854f87923db99c8fb874 Commit 23bde34771f1 ("KVM: arm64: vgic-v3: Drop the reporting of GICR_TYPER.Last for userspace") temporarily fixed a bug identified when attempting to access the GICR_TYPER register before the redistributor region setting, but dropped the support of the LAST bit. Emulating the GICR_TYPER.Last bit still makes sense for architecture compliance though. This patch restores its support (if the redistributor region was set) while keeping the code safe. We introduce a new helper, vgic_mmio_vcpu_rdist_is_last() which computes whether a redistributor is the highest one of a series of redistributor contributor pages. With this new implementation we do not need to have a uaccess read accessor anymore. Signed-off-by: Eric Auger <eric.auger@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210405163941.510258-9-eric.auger@redhat.com 
Commit 23bde34771f1 ("KVM: arm64: vgic-v3: Drop the
reporting of GICR_TYPER.Last for userspace") temporarily fixed
a bug identified when attempting to access the GICR_TYPER
register before the redistributor region setting, but dropped
the support of the LAST bit.

Emulating the GICR_TYPER.Last bit still makes sense for
architecture compliance though. This patch restores its support
(if the redistributor region was set) while keeping the code safe.

We introduce a new helper, vgic_mmio_vcpu_rdist_is_last() which
computes whether a redistributor is the highest one of a series
of redistributor contributor pages.

With this new implementation we do not need to have a uaccess
read accessor anymore.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210405163941.510258-9-eric.auger@redhat.com
KVM: arm64: Turn kvm_arm_support_pmu_v3() into a static key 2021-03-06T09:18:40+00:00 Marc Zyngier maz@kernel.org 2021-03-05T18:52:50+00:00 6b5b368fccd7109b052e45af8ba1464c8d140a49 We currently find out about the presence of a HW PMU (or the handling of that PMU by perf, which amounts to the same thing) in a fairly roundabout way, by checking the number of counters available to perf. That's good enough for now, but we will soon need to find about about that on paths where perf is out of reach (in the world switch). Instead, let's turn kvm_arm_support_pmu_v3() into a static key. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Link: https://lore.kernel.org/r/20210209114844.3278746-2-maz@kernel.org Message-Id: <20210305185254.3730990-5-maz@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> 
We currently find out about the presence of a HW PMU (or the handling
of that PMU by perf, which amounts to the same thing) in a fairly
roundabout way, by checking the number of counters available to perf.
That's good enough for now, but we will soon need to find about about
that on paths where perf is out of reach (in the world switch).

Instead, let's turn kvm_arm_support_pmu_v3() into a static key.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Link: https://lore.kernel.org/r/20210209114844.3278746-2-maz@kernel.org
Message-Id: <20210305185254.3730990-5-maz@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM: arm64: Replace KVM_ARM_PMU with HW_PERF_EVENTS 2021-01-04T16:50:16+00:00 Marc Zyngier maz@kernel.org 2021-01-04T16:50:16+00:00 8cbebc4118b5933b3ae6351ceb433f75ac6b7c6b KVM_ARM_PMU only existed for the benefit of 32bit ARM hosts, and makes no sense now that we are 64bit only. Get rid of it. Signed-off-by: Marc Zyngier <maz@kernel.org> 
KVM_ARM_PMU only existed for the benefit of 32bit ARM hosts,
and makes no sense now that we are 64bit only. Get rid of it.

Signed-off-by: Marc Zyngier <maz@kernel.org>