[PATCH v4 32/32] KVM: x86: Track required APICv inhibits with variable, not callback

From: Sean Christopherson
Date: Fri Sep 30 2022 - 21:04:08 EST

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In reply to: Sean Christopherson: "[PATCH v4 31/32] Revert "KVM: SVM: Do not throw warning when calling avic_vcpu_load on a running vcpu""
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Track the per-vendor required APICv inhibits with a variable instead of
calling into vendor code every time KVM wants to query the set of
required inhibits. The required inhibits are a property of the vendor's
virtualization architecture, i.e. are 100% static.

Using a variable allows the compiler to inline the check, e.g. generate
a single-uop TEST+Jcc, and thus eliminates any desire to avoid checking
inhibits for performance reasons.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/include/asm/kvm-x86-ops.h | 1 -
arch/x86/include/asm/kvm_host.h | 2 +-
arch/x86/kvm/svm/avic.c | 20 --------------------
arch/x86/kvm/svm/svm.c | 2 +-
arch/x86/kvm/svm/svm.h | 17 ++++++++++++++++-
arch/x86/kvm/vmx/vmx.c | 24 +++++++++++-------------
arch/x86/kvm/x86.c | 9 +++++++--
7 files changed, 36 insertions(+), 39 deletions(-)

diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 82ba4a564e58..533d0e804e5a 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -76,7 +76,6 @@ KVM_X86_OP(set_nmi_mask)
KVM_X86_OP(enable_nmi_window)
KVM_X86_OP(enable_irq_window)
KVM_X86_OP_OPTIONAL(update_cr8_intercept)
-KVM_X86_OP(check_apicv_inhibit_reasons)
KVM_X86_OP(refresh_apicv_exec_ctrl)
KVM_X86_OP_OPTIONAL(hwapic_irr_update)
KVM_X86_OP_OPTIONAL(hwapic_isr_update)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 4fd06965c773..41d1c684a1e1 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1566,7 +1566,7 @@ struct kvm_x86_ops {
void (*enable_nmi_window)(struct kvm_vcpu *vcpu);
void (*enable_irq_window)(struct kvm_vcpu *vcpu);
void (*update_cr8_intercept)(struct kvm_vcpu *vcpu, int tpr, int irr);
- bool (*check_apicv_inhibit_reasons)(enum kvm_apicv_inhibit reason);
+ const unsigned long required_apicv_inhibits;
void (*refresh_apicv_exec_ctrl)(struct kvm_vcpu *vcpu);
void (*hwapic_irr_update)(struct kvm_vcpu *vcpu, int max_irr);
void (*hwapic_isr_update)(int isr);
diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index 35b0ef877e53..5b25944274b5 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -966,26 +966,6 @@ int avic_pi_update_irte(struct kvm *kvm, unsigned int host_irq,
return ret;
}

-bool avic_check_apicv_inhibit_reasons(enum kvm_apicv_inhibit reason)
-{
- ulong supported = BIT(APICV_INHIBIT_REASON_DISABLE) |
- BIT(APICV_INHIBIT_REASON_ABSENT) |
- BIT(APICV_INHIBIT_REASON_HYPERV) |
- BIT(APICV_INHIBIT_REASON_NESTED) |
- BIT(APICV_INHIBIT_REASON_IRQWIN) |
- BIT(APICV_INHIBIT_REASON_PIT_REINJ) |
- BIT(APICV_INHIBIT_REASON_BLOCKIRQ) |
- BIT(APICV_INHIBIT_REASON_SEV) |
- BIT(APICV_INHIBIT_REASON_PHYSICAL_ID_ALIASED) |
- BIT(APICV_INHIBIT_REASON_APIC_ID_MODIFIED) |
- BIT(APICV_INHIBIT_REASON_APIC_BASE_MODIFIED) |
- BIT(APICV_INHIBIT_REASON_X2APIC) |
- BIT(APICV_INHIBIT_REASON_LOGICAL_ID_ALIASED);
-
- return supported & BIT(reason);
-}
-
-
static inline int
avic_update_iommu_vcpu_affinity(struct kvm_vcpu *vcpu, int cpu, bool r)
{
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 37fe7bcf8496..6bca3f9f39e6 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4800,8 +4800,8 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
.update_cr8_intercept = svm_update_cr8_intercept,
.set_virtual_apic_mode = avic_refresh_virtual_apic_mode,
.refresh_apicv_exec_ctrl = avic_refresh_apicv_exec_ctrl,
- .check_apicv_inhibit_reasons = avic_check_apicv_inhibit_reasons,
.apicv_post_state_restore = avic_apicv_post_state_restore,
+ .required_apicv_inhibits = AVIC_REQUIRED_APICV_INHIBITS,

.get_exit_info = svm_get_exit_info,

diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 29c334a932c3..dfde85782da5 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -619,6 +619,22 @@ void svm_switch_vmcb(struct vcpu_svm *svm, struct kvm_vmcb_info *target_vmcb);
extern struct kvm_x86_nested_ops svm_nested_ops;

/* avic.c */
+#define AVIC_REQUIRED_APICV_INHIBITS \
+( \
+ BIT(APICV_INHIBIT_REASON_DISABLE) | \
+ BIT(APICV_INHIBIT_REASON_ABSENT) | \
+ BIT(APICV_INHIBIT_REASON_HYPERV) | \
+ BIT(APICV_INHIBIT_REASON_NESTED) | \
+ BIT(APICV_INHIBIT_REASON_IRQWIN) | \
+ BIT(APICV_INHIBIT_REASON_PIT_REINJ) | \
+ BIT(APICV_INHIBIT_REASON_BLOCKIRQ) | \
+ BIT(APICV_INHIBIT_REASON_SEV) | \
+ BIT(APICV_INHIBIT_REASON_PHYSICAL_ID_ALIASED) | \
+ BIT(APICV_INHIBIT_REASON_APIC_ID_MODIFIED) | \
+ BIT(APICV_INHIBIT_REASON_APIC_BASE_MODIFIED) | \
+ BIT(APICV_INHIBIT_REASON_X2APIC) | \
+ BIT(APICV_INHIBIT_REASON_LOGICAL_ID_ALIASED) \
+)

bool avic_hardware_setup(struct kvm_x86_ops *ops);
int avic_ga_log_notifier(u32 ga_tag);
@@ -632,7 +648,6 @@ void avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu);
void avic_vcpu_put(struct kvm_vcpu *vcpu);
void avic_apicv_post_state_restore(struct kvm_vcpu *vcpu);
void avic_refresh_apicv_exec_ctrl(struct kvm_vcpu *vcpu);
-bool avic_check_apicv_inhibit_reasons(enum kvm_apicv_inhibit reason);
int avic_pi_update_irte(struct kvm *kvm, unsigned int host_irq,
uint32_t guest_irq, bool set);
void avic_vcpu_blocking(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 5920166d7260..54bc447ba87e 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7949,18 +7949,16 @@ static void vmx_hardware_unsetup(void)
free_kvm_area();
}

-static bool vmx_check_apicv_inhibit_reasons(enum kvm_apicv_inhibit reason)
-{
- ulong supported = BIT(APICV_INHIBIT_REASON_DISABLE) |
- BIT(APICV_INHIBIT_REASON_ABSENT) |
- BIT(APICV_INHIBIT_REASON_HYPERV) |
- BIT(APICV_INHIBIT_REASON_BLOCKIRQ) |
- BIT(APICV_INHIBIT_REASON_PHYSICAL_ID_ALIASED) |
- BIT(APICV_INHIBIT_REASON_APIC_ID_MODIFIED) |
- BIT(APICV_INHIBIT_REASON_APIC_BASE_MODIFIED);
-
- return supported & BIT(reason);
-}
+#define VMX_REQUIRED_APICV_INHIBITS \
+( \
+ BIT(APICV_INHIBIT_REASON_DISABLE)| \
+ BIT(APICV_INHIBIT_REASON_ABSENT) | \
+ BIT(APICV_INHIBIT_REASON_HYPERV) | \
+ BIT(APICV_INHIBIT_REASON_BLOCKIRQ) | \
+ BIT(APICV_INHIBIT_REASON_PHYSICAL_ID_ALIASED) | \
+ BIT(APICV_INHIBIT_REASON_APIC_ID_MODIFIED) | \
+ BIT(APICV_INHIBIT_REASON_APIC_BASE_MODIFIED) \
+)

static void vmx_vm_destroy(struct kvm *kvm)
{
@@ -8044,7 +8042,7 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = {
.refresh_apicv_exec_ctrl = vmx_refresh_apicv_exec_ctrl,
.load_eoi_exitmap = vmx_load_eoi_exitmap,
.apicv_post_state_restore = vmx_apicv_post_state_restore,
- .check_apicv_inhibit_reasons = vmx_check_apicv_inhibit_reasons,
+ .required_apicv_inhibits = VMX_REQUIRED_APICV_INHIBITS,
.hwapic_irr_update = vmx_hwapic_irr_update,
.hwapic_isr_update = vmx_hwapic_isr_update,
.guest_apic_has_interrupt = vmx_guest_apic_has_interrupt,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a20002924eb4..b307637d9200 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10251,6 +10251,11 @@ void kvm_make_scan_ioapic_request(struct kvm *kvm)
kvm_make_all_cpus_request(kvm, KVM_REQ_SCAN_IOAPIC);
}

+static bool kvm_is_required_apicv_inhibit(enum kvm_apicv_inhibit reason)
+{
+ return kvm_x86_ops.required_apicv_inhibits & BIT(reason);
+}
+
void __kvm_vcpu_update_apicv(struct kvm_vcpu *vcpu)
{
struct kvm_lapic *apic = vcpu->arch.apic;
@@ -10294,7 +10299,7 @@ static void kvm_vcpu_update_apicv(struct kvm_vcpu *vcpu)
return;

if (apic_x2apic_mode(vcpu->arch.apic) &&
- static_call(kvm_x86_check_apicv_inhibit_reasons)(APICV_INHIBIT_REASON_X2APIC))
+ kvm_is_required_apicv_inhibit(APICV_INHIBIT_REASON_X2APIC))
kvm_inhibit_apic_access_page(vcpu);

__kvm_vcpu_update_apicv(vcpu);
@@ -10307,7 +10312,7 @@ void __kvm_set_or_clear_apicv_inhibit(struct kvm *kvm,

lockdep_assert_held_write(&kvm->arch.apicv_update_lock);

- if (!static_call(kvm_x86_check_apicv_inhibit_reasons)(reason))
+ if (!kvm_is_required_apicv_inhibit(reason))
return;

old = new = kvm->arch.apicv_inhibit_reasons;
--
2.38.0.rc1.362.ged0d419d3c-goog

Next message: Kevin Mitchell: "[PATCH] netdevice: don't warn when capping txqueue 0"
Previous message: Sean Christopherson: "[PATCH v4 31/32] Revert "KVM: SVM: Do not throw warning when calling avic_vcpu_load on a running vcpu""
In reply to: Sean Christopherson: "[PATCH v4 31/32] Revert "KVM: SVM: Do not throw warning when calling avic_vcpu_load on a running vcpu""
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]