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Date: Tue, 29 Nov 2022 21:37:10 +0200
From: Maxim Levitsky <mlevitsk@...hat.com>
To: kvm@...r.kernel.org
Cc: Sandipan Das <sandipan.das@....com>,
Paolo Bonzini <pbonzini@...hat.com>,
Jim Mattson <jmattson@...gle.com>,
Peter Zijlstra <peterz@...radead.org>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Borislav Petkov <bp@...en8.de>,
Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
Josh Poimboeuf <jpoimboe@...nel.org>,
Daniel Sneddon <daniel.sneddon@...ux.intel.com>,
Jiaxi Chen <jiaxi.chen@...ux.intel.com>,
Babu Moger <babu.moger@....com>, linux-kernel@...r.kernel.org,
Jing Liu <jing2.liu@...el.com>,
Wyes Karny <wyes.karny@....com>, x86@...nel.org,
"H. Peter Anvin" <hpa@...or.com>,
Sean Christopherson <seanjc@...gle.com>,
Maxim Levitsky <mlevitsk@...hat.com>
Subject: [PATCH v2 04/11] KVM: SVM: drop the SVM specific H_FLAGS
GIF and 'waiting for IRET' are used only for the SVM and thus should
not be in H_FLAGS.
NMI mask is not x86 specific but it is only used for SVM without vNMI.
The VMX have similar concept of NMI mask (soft_vnmi_blocked),
and it is used when its 'vNMI' feature is not enabled,
but because the VMX can't intercept IRET, it is more of a hack,
and thus should not use common host flags either.
No functional change is intended.
Suggested-by: Sean Christopherson <seanjc@...gle.com>
Signed-off-by: Maxim Levitsky <mlevitsk@...hat.com>
---
arch/x86/include/asm/kvm_host.h | 3 ---
arch/x86/kvm/svm/svm.c | 22 +++++++++++++---------
arch/x86/kvm/svm/svm.h | 25 ++++++++++++++++++++++---
3 files changed, 35 insertions(+), 15 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 70af7240a1d5af..9208ad7a6bd004 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -2052,9 +2052,6 @@ enum {
TASK_SWITCH_GATE = 3,
};
-#define HF_GIF_MASK (1 << 0)
-#define HF_NMI_MASK (1 << 3)
-#define HF_IRET_MASK (1 << 4)
#define HF_GUEST_MASK (1 << 5) /* VCPU is in guest-mode */
#ifdef CONFIG_KVM_SMM
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 91352d69284524..512b2aa21137e2 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1326,6 +1326,9 @@ static void __svm_vcpu_reset(struct kvm_vcpu *vcpu)
vcpu->arch.microcode_version = 0x01000065;
svm->tsc_ratio_msr = kvm_caps.default_tsc_scaling_ratio;
+ svm->nmi_masked = false;
+ svm->awaiting_iret_completion = false;
+
if (sev_es_guest(vcpu->kvm))
sev_es_vcpu_reset(svm);
}
@@ -2470,7 +2473,7 @@ static int iret_interception(struct kvm_vcpu *vcpu)
struct vcpu_svm *svm = to_svm(vcpu);
++vcpu->stat.nmi_window_exits;
- vcpu->arch.hflags |= HF_IRET_MASK;
+ svm->awaiting_iret_completion = true;
if (!sev_es_guest(vcpu->kvm)) {
svm_clr_intercept(svm, INTERCEPT_IRET);
svm->nmi_iret_rip = kvm_rip_read(vcpu);
@@ -3466,7 +3469,7 @@ static void svm_inject_nmi(struct kvm_vcpu *vcpu)
if (svm->nmi_l1_to_l2)
return;
- vcpu->arch.hflags |= HF_NMI_MASK;
+ svm->nmi_masked = true;
if (!sev_es_guest(vcpu->kvm))
svm_set_intercept(svm, INTERCEPT_IRET);
++vcpu->stat.nmi_injections;
@@ -3580,7 +3583,7 @@ bool svm_nmi_blocked(struct kvm_vcpu *vcpu)
return false;
ret = (vmcb->control.int_state & SVM_INTERRUPT_SHADOW_MASK) ||
- (vcpu->arch.hflags & HF_NMI_MASK);
+ (svm->nmi_masked);
return ret;
}
@@ -3602,7 +3605,7 @@ static int svm_nmi_allowed(struct kvm_vcpu *vcpu, bool for_injection)
static bool svm_get_nmi_mask(struct kvm_vcpu *vcpu)
{
- return !!(vcpu->arch.hflags & HF_NMI_MASK);
+ return to_svm(vcpu)->nmi_masked;
}
static void svm_set_nmi_mask(struct kvm_vcpu *vcpu, bool masked)
@@ -3610,11 +3613,11 @@ static void svm_set_nmi_mask(struct kvm_vcpu *vcpu, bool masked)
struct vcpu_svm *svm = to_svm(vcpu);
if (masked) {
- vcpu->arch.hflags |= HF_NMI_MASK;
+ svm->nmi_masked = true;
if (!sev_es_guest(vcpu->kvm))
svm_set_intercept(svm, INTERCEPT_IRET);
} else {
- vcpu->arch.hflags &= ~HF_NMI_MASK;
+ svm->nmi_masked = false;
if (!sev_es_guest(vcpu->kvm))
svm_clr_intercept(svm, INTERCEPT_IRET);
}
@@ -3700,7 +3703,7 @@ static void svm_enable_nmi_window(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);
- if ((vcpu->arch.hflags & (HF_NMI_MASK | HF_IRET_MASK)) == HF_NMI_MASK)
+ if (svm->nmi_masked && !svm->awaiting_iret_completion)
return; /* IRET will cause a vm exit */
if (!gif_set(svm)) {
@@ -3824,10 +3827,11 @@ static void svm_complete_interrupts(struct kvm_vcpu *vcpu)
* If we've made progress since setting HF_IRET_MASK, we've
* executed an IRET and can allow NMI injection.
*/
- if ((vcpu->arch.hflags & HF_IRET_MASK) &&
+ if (svm->awaiting_iret_completion &&
(sev_es_guest(vcpu->kvm) ||
kvm_rip_read(vcpu) != svm->nmi_iret_rip)) {
- vcpu->arch.hflags &= ~(HF_NMI_MASK | HF_IRET_MASK);
+ svm->awaiting_iret_completion = false;
+ svm->nmi_masked = false;
kvm_make_request(KVM_REQ_EVENT, vcpu);
}
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 4826e6cc611bf1..587ddc150f9f34 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -237,8 +237,24 @@ struct vcpu_svm {
struct svm_nested_state nested;
+ /* NMI mask value, used when vNMI is not enabled */
+ bool nmi_masked;
+
+ /*
+ * True when the NMI still masked but guest IRET was just intercepted
+ * and KVM is waiting for RIP change which will signal that this IRET was
+ * retired and thus NMI can be unmasked.
+ */
+ bool awaiting_iret_completion;
+
+ /*
+ * Set when KVM waits for IRET completion and needs to
+ * inject NMIs as soon as it completes (e.g NMI is pending injection).
+ * The KVM takes over EFLAGS.TF for this.
+ */
bool nmi_singlestep;
u64 nmi_singlestep_guest_rflags;
+
bool nmi_l1_to_l2;
unsigned long soft_int_csbase;
@@ -280,6 +296,9 @@ struct vcpu_svm {
bool guest_state_loaded;
bool x2avic_msrs_intercepted;
+
+ /* Guest GIF value which is used when vGIF is not enabled */
+ bool gif_value;
};
struct svm_cpu_data {
@@ -497,7 +516,7 @@ static inline void enable_gif(struct vcpu_svm *svm)
if (vmcb)
vmcb->control.int_ctl |= V_GIF_MASK;
else
- svm->vcpu.arch.hflags |= HF_GIF_MASK;
+ svm->gif_value = true;
}
static inline void disable_gif(struct vcpu_svm *svm)
@@ -507,7 +526,7 @@ static inline void disable_gif(struct vcpu_svm *svm)
if (vmcb)
vmcb->control.int_ctl &= ~V_GIF_MASK;
else
- svm->vcpu.arch.hflags &= ~HF_GIF_MASK;
+ svm->gif_value = false;
}
static inline bool gif_set(struct vcpu_svm *svm)
@@ -517,7 +536,7 @@ static inline bool gif_set(struct vcpu_svm *svm)
if (vmcb)
return !!(vmcb->control.int_ctl & V_GIF_MASK);
else
- return !!(svm->vcpu.arch.hflags & HF_GIF_MASK);
+ return svm->gif_value;
}
static inline bool nested_npt_enabled(struct vcpu_svm *svm)
--
2.26.3
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