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Date: Fri, 27 Aug 2021 17:35:53 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Will Deacon <will@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Catalin Marinas <catalin.marinas@....com>,
Marc Zyngier <maz@...nel.org>, Guo Ren <guoren@...nel.org>,
Nick Hu <nickhu@...estech.com>,
Greentime Hu <green.hu@...il.com>,
Vincent Chen <deanbo422@...il.com>,
Paul Walmsley <paul.walmsley@...ive.com>,
Palmer Dabbelt <palmer@...belt.com>,
Albert Ou <aou@...s.berkeley.edu>,
Thomas Gleixner <tglx@...utronix.de>,
Borislav Petkov <bp@...en8.de>, x86@...nel.org,
Paolo Bonzini <pbonzini@...hat.com>,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
Juergen Gross <jgross@...e.com>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...hat.com>,
Namhyung Kim <namhyung@...nel.org>,
James Morse <james.morse@....com>,
Alexandru Elisei <alexandru.elisei@....com>,
Suzuki K Poulose <suzuki.poulose@....com>,
"H. Peter Anvin" <hpa@...or.com>,
Sean Christopherson <seanjc@...gle.com>,
Vitaly Kuznetsov <vkuznets@...hat.com>,
Wanpeng Li <wanpengli@...cent.com>,
Jim Mattson <jmattson@...gle.com>,
Joerg Roedel <joro@...tes.org>,
Stefano Stabellini <sstabellini@...nel.org>,
linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
linux-csky@...r.kernel.org, linux-riscv@...ts.infradead.org,
kvm@...r.kernel.org, xen-devel@...ts.xenproject.org,
Artem Kashkanov <artem.kashkanov@...el.com>,
Like Xu <like.xu.linux@...il.com>,
Zhu Lingshan <lingshan.zhu@...el.com>
Subject: [PATCH v2 08/13] KVM: x86: Drop current_vcpu for kvm_running_vcpu +
kvm_arch_vcpu variable
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@...gle.com>
---
arch/x86/include/asm/kvm_host.h | 3 +--
arch/x86/kvm/pmu.c | 2 +-
arch/x86/kvm/x86.c | 21 ++++++++++++---------
arch/x86/kvm/x86.h | 10 ++++++----
4 files changed, 20 insertions(+), 16 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 1080166fc0cf..2d86a2dfc775 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -763,6 +763,7 @@ 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;
@@ -1874,8 +1875,6 @@ 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);
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 5b68d4188de0..eef48258e50f 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -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);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b2a4d085aa4f..6df300c55461 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8264,15 +8264,17 @@ 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);
+static inline bool kvm_pmi_in_guest(struct kvm_vcpu *vcpu)
+{
+ return vcpu && vcpu->arch.handling_intr_from_guest;
+}
-unsigned int kvm_guest_state(void)
+static unsigned int kvm_guest_state(void)
{
- struct kvm_vcpu *vcpu = __this_cpu_read(current_vcpu);
+ 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;
@@ -8284,9 +8286,10 @@ 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);
@@ -8294,10 +8297,10 @@ 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);
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 7d66d63dc55a..a9c107e7c907 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -387,18 +387,20 @@ 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)
{
--
2.33.0.259.gc128427fd7-goog
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