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Merge branch kvm-arm64/generic-entry into kvmarm-master/next

Browse source 
Switch KVM/arm64 to the generic entry code, courtesy of Oliver Upton

* kvm-arm64/generic-entry:
  KVM: arm64: Use generic KVM xfer to guest work function
  entry: KVM: Allow use of generic KVM entry w/o full generic support
  KVM: arm64: Record number of signal exits as a vCPU stat

Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Marc Zyngier 2021-08-20 12:23:09 +01:00
commit ca3385a507
5 changed files with 52 additions and 28 deletions
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1
arch/arm64/include/asm/kvm_host.h
View file

@ -575,6 +575,7 @@ struct kvm_vcpu_stat {
u64 wfi_exit_stat;
u64 mmio_exit_user;
u64 mmio_exit_kernel;
u64 signal_exits;
u64 exits;
};

1
arch/arm64/kvm/Kconfig
View file

@ -26,6 +26,7 @@ menuconfig KVM
select HAVE_KVM_ARCH_TLB_FLUSH_ALL
select KVM_MMIO
select KVM_GENERIC_DIRTYLOG_READ_PROTECT
select KVM_XFER_TO_GUEST_WORK
select SRCU
select KVM_VFIO
select HAVE_KVM_EVENTFD

71
arch/arm64/kvm/arm.c
View file

@ -6,6 +6,7 @@
#include <linux/bug.h>
#include <linux/cpu_pm.h>
#include <linux/entry-kvm.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/kvm_host.h>
@ -715,6 +716,45 @@ static bool vcpu_mode_is_bad_32bit(struct kvm_vcpu *vcpu)
static_branch_unlikely(&arm64_mismatched_32bit_el0);
}
/**
* kvm_vcpu_exit_request - returns true if the VCPU should *not* enter the guest
* @vcpu: The VCPU pointer
* @ret: Pointer to write optional return code
*
* Returns: true if the VCPU needs to return to a preemptible + interruptible
* and skip guest entry.
*
* This function disambiguates between two different types of exits: exits to a
* preemptible + interruptible kernel context and exits to userspace. For an
* exit to userspace, this function will write the return code to ret and return
* true. For an exit to preemptible + interruptible kernel context (i.e. check
* for pending work and re-enter), return true without writing to ret.
*/
static bool kvm_vcpu_exit_request(struct kvm_vcpu *vcpu, int *ret)
{
struct kvm_run *run = vcpu->run;
/*
* If we're using a userspace irqchip, then check if we need
* to tell a userspace irqchip about timer or PMU level
* changes and if so, exit to userspace (the actual level
* state gets updated in kvm_timer_update_run and
* kvm_pmu_update_run below).
*/
if (static_branch_unlikely(&userspace_irqchip_in_use)) {
if (kvm_timer_should_notify_user(vcpu) ||
kvm_pmu_should_notify_user(vcpu)) {
*ret = -EINTR;
run->exit_reason = KVM_EXIT_INTR;
return true;
}
}
return kvm_request_pending(vcpu) ||
need_new_vmid_gen(&vcpu->arch.hw_mmu->vmid) ||
xfer_to_guest_mode_work_pending();
}
/**
* kvm_arch_vcpu_ioctl_run - the main VCPU run function to execute guest code
* @vcpu: The VCPU pointer
@ -758,7 +798,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
/*
* Check conditions before entering the guest
*/
cond_resched();
ret = xfer_to_guest_mode_handle_work(vcpu);
if (!ret)
ret = 1;
update_vmid(&vcpu->arch.hw_mmu->vmid);
@ -777,30 +819,6 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
kvm_vgic_flush_hwstate(vcpu);
/*
* Exit if we have a signal pending so that we can deliver the
* signal to user space.
*/
if (signal_pending(current)) {
ret = -EINTR;
run->exit_reason = KVM_EXIT_INTR;
}
/*
* If we're using a userspace irqchip, then check if we need
* to tell a userspace irqchip about timer or PMU level
* changes and if so, exit to userspace (the actual level
* state gets updated in kvm_timer_update_run and
* kvm_pmu_update_run below).
*/
if (static_branch_unlikely(&userspace_irqchip_in_use)) {
if (kvm_timer_should_notify_user(vcpu) ||
kvm_pmu_should_notify_user(vcpu)) {
ret = -EINTR;
run->exit_reason = KVM_EXIT_INTR;
}
}
/*
* Ensure we set mode to IN_GUEST_MODE after we disable
* interrupts and before the final VCPU requests check.
@ -809,8 +827,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
*/
smp_store_mb(vcpu->mode, IN_GUEST_MODE);
if (ret <= 0 || need_new_vmid_gen(&vcpu->arch.hw_mmu->vmid) ||
kvm_request_pending(vcpu)) {
if (ret <= 0 || kvm_vcpu_exit_request(vcpu, &ret)) {
vcpu->mode = OUTSIDE_GUEST_MODE;
isb(); /* Ensure work in x_flush_hwstate is committed */
kvm_pmu_sync_hwstate(vcpu);

1
arch/arm64/kvm/guest.c
View file

@ -50,6 +50,7 @@ const struct _kvm_stats_desc kvm_vcpu_stats_desc[] = {
STATS_DESC_COUNTER(VCPU, wfi_exit_stat),
STATS_DESC_COUNTER(VCPU, mmio_exit_user),
STATS_DESC_COUNTER(VCPU, mmio_exit_kernel),
STATS_DESC_COUNTER(VCPU, signal_exits),
STATS_DESC_COUNTER(VCPU, exits)
};
static_assert(ARRAY_SIZE(kvm_vcpu_stats_desc) ==

6
include/linux/entry-kvm.h
View file

@ -2,7 +2,11 @@
#ifndef __LINUX_ENTRYKVM_H
#define __LINUX_ENTRYKVM_H
#include <linux/entry-common.h>
#include <linux/static_call_types.h>
#include <linux/tracehook.h>
#include <linux/syscalls.h>
#include <linux/seccomp.h>
#include <linux/sched.h>
#include <linux/tick.h>
/* Transfer to guest mode work */