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KVM: x86: Drop current_vcpu for kvm_running_vcpu + kvm_arch_vcpu variable

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Use the generic kvm_running_vcpu plus a new 'handling_intr_from_guest'
variable in kvm_arch_vcpu instead of the semi-redundant current_vcpu.
kvm_before/after_interrupt() must be called while the vCPU is loaded,
(which protects against preemption), thus kvm_running_vcpu is guaranteed
to be non-NULL when handling_intr_from_guest is non-zero.

Switching to kvm_get_running_vcpu() will allows moving KVM's perf
callbacks to generic code, and the new flag will be used in a future
patch to more precisely identify the "NMI from guest" case.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lore.kernel.org/r/20211111020738.2512932-11-seanjc@google.com
This commit is contained in:
Sean Christopherson 2021-11-11 02:07:31 +00:00 committed by Peter Zijlstra
parent 87b940a067
commit 73cd107b96
4 changed files with 21 additions and 17 deletions
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3
arch/x86/include/asm/kvm_host.h
View File

@ -773,6 +773,7 @@ struct kvm_vcpu_arch {
unsigned nmi_pending; /* NMI queued after currently running handler */
bool nmi_injected; /* Trying to inject an NMI this entry */
bool smi_pending; /* SMI queued after currently running handler */
u8 handling_intr_from_guest;
struct kvm_mtrr mtrr_state;
u64 pat;
@ -1895,8 +1896,6 @@ int kvm_skip_emulated_instruction(struct kvm_vcpu *vcpu);
int kvm_complete_insn_gp(struct kvm_vcpu *vcpu, int err);
void __kvm_request_immediate_exit(struct kvm_vcpu *vcpu);
unsigned int kvm_guest_state(void);
void __user *__x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa,
u32 size);
bool kvm_vcpu_is_reset_bsp(struct kvm_vcpu *vcpu);

2
arch/x86/kvm/pmu.c
View File

@ -87,7 +87,7 @@ static void kvm_perf_overflow_intr(struct perf_event *perf_event,
* woken up. So we should wake it, but this is impossible from
* NMI context. Do it from irq work instead.
*/
if (!kvm_guest_state())
if (!kvm_handling_nmi_from_guest(pmc->vcpu))
irq_work_queue(&pmc_to_pmu(pmc)->irq_work);
else
kvm_make_request(KVM_REQ_PMI, pmc->vcpu);

23
arch/x86/kvm/x86.c
View File

@ -8469,15 +8469,17 @@ static void kvm_timer_init(void)
kvmclock_cpu_online, kvmclock_cpu_down_prep);
}
DEFINE_PER_CPU(struct kvm_vcpu *, current_vcpu);
EXPORT_PER_CPU_SYMBOL_GPL(current_vcpu);
unsigned int kvm_guest_state(void)
static inline bool kvm_pmi_in_guest(struct kvm_vcpu *vcpu)
{
struct kvm_vcpu *vcpu = __this_cpu_read(current_vcpu);
return vcpu && vcpu->arch.handling_intr_from_guest;
}
static unsigned int kvm_guest_state(void)
{
struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
unsigned int state;
if (!vcpu)
if (!kvm_pmi_in_guest(vcpu))
return 0;
state = PERF_GUEST_ACTIVE;
@ -8489,9 +8491,10 @@ unsigned int kvm_guest_state(void)
static unsigned long kvm_guest_get_ip(void)
{
struct kvm_vcpu *vcpu = __this_cpu_read(current_vcpu);
struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
if (WARN_ON_ONCE(!vcpu))
/* Retrieving the IP must be guarded by a call to kvm_guest_state(). */
if (WARN_ON_ONCE(!kvm_pmi_in_guest(vcpu)))
return 0;
return kvm_rip_read(vcpu);
@ -8499,10 +8502,10 @@ static unsigned long kvm_guest_get_ip(void)
static unsigned int kvm_handle_intel_pt_intr(void)
{
struct kvm_vcpu *vcpu = __this_cpu_read(current_vcpu);
struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
/* '0' on failure so that the !PT case can use a RET0 static call. */
if (!vcpu)
if (!kvm_pmi_in_guest(vcpu))
return 0;
kvm_make_request(KVM_REQ_PMI, vcpu);

10
arch/x86/kvm/x86.h
View File

@ -385,18 +385,20 @@ static inline bool kvm_cstate_in_guest(struct kvm *kvm)
return kvm->arch.cstate_in_guest;
}
DECLARE_PER_CPU(struct kvm_vcpu *, current_vcpu);
static inline void kvm_before_interrupt(struct kvm_vcpu *vcpu)
{
__this_cpu_write(current_vcpu, vcpu);
WRITE_ONCE(vcpu->arch.handling_intr_from_guest, 1);
}
static inline void kvm_after_interrupt(struct kvm_vcpu *vcpu)
{
__this_cpu_write(current_vcpu, NULL);
WRITE_ONCE(vcpu->arch.handling_intr_from_guest, 0);
}
static inline bool kvm_handling_nmi_from_guest(struct kvm_vcpu *vcpu)
{
return !!vcpu->arch.handling_intr_from_guest;
}
static inline bool kvm_pat_valid(u64 data)
{