On 2016/9/28 5:20, Paolo Bonzini wrote:
Calling apic_find_highest_irr results in IRR being scanned twice,
once in vmx_sync_pir_from_irr and once in apic_search_irr.  Change
vcpu_enter_guest to use sync_pir_from_irr (with a new argument to
trigger the RVI write), and let sync_pir_from_irr get the new RVI
directly from kvm_apic_update_irr.

Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
 arch/x86/include/asm/kvm_host.h |  2 +-
 arch/x86/kvm/lapic.c            | 25 ++++++++++++++++---------
 arch/x86/kvm/lapic.h            |  4 ++--
 arch/x86/kvm/svm.c              |  2 +-
 arch/x86/kvm/vmx.c              | 25 ++++++++++++++-----------
 arch/x86/kvm/x86.c              |  7 +++----
 6 files changed, 37 insertions(+), 28 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 4b20f7304b9c..f73eea243567 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -941,7 +941,7 @@ struct kvm_x86_ops {
        void (*set_virtual_x2apic_mode)(struct kvm_vcpu *vcpu, bool set);
        void (*set_apic_access_page_addr)(struct kvm_vcpu *vcpu, hpa_t hpa);
        void (*deliver_posted_interrupt)(struct kvm_vcpu *vcpu, int vector);
-       void (*sync_pir_to_irr)(struct kvm_vcpu *vcpu);
+       void (*sync_pir_to_irr)(struct kvm_vcpu *vcpu, bool sync_rvi);
        int (*set_tss_addr)(struct kvm *kvm, unsigned int addr);
        int (*get_tdp_level)(void);
        u64 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio);
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index be8b7ad56dd1..85b79b90e3d0 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -317,7 +317,7 @@ static int find_highest_vector(void *bitmap)
             vec >= 0; vec -= APIC_VECTORS_PER_REG) {
                reg = bitmap + REG_POS(vec);
                if (*reg)
-                       return fls(*reg) - 1 + vec;
+                       return __fls(*reg) + vec;
        }

        return -1;
@@ -337,25 +337,32 @@ static u8 count_vectors(void *bitmap)
        return count;
 }

-void __kvm_apic_update_irr(u32 *pir, void *regs)
+int __kvm_apic_update_irr(u32 *pir, void *regs)
 {
-       u32 i, pir_val;
+       u32 i, vec;
+       u32 pir_val, irr_val;
+       int max_irr = -1;

-       for (i = 0; i <= 7; i++) {
+       for (i = vec = 0; i <= 7; i++, vec += 32) {

how about ignore the first 32 vectors since they cannot be used as normal interrupt except nmi interrupt which is special handled.

                pir_val = READ_ONCE(pir[i]);
+               irr_val = *((u32 *)(regs + APIC_IRR + i * 0x10));
                if (pir_val) {
-                       pir_val = xchg(&pir[i], 0);
-                       *((u32 *)(regs + APIC_IRR + i * 0x10)) |= pir_val;
+                       irr_val |= xchg(&pir[i], 0);
+                       *((u32 *)(regs + APIC_IRR + i * 0x10)) = irr_val;
                }
+               if (irr_val)
+                       max_irr = __fls(irr_val) + vec;
        }
+
+       return max_irr;
 }
 EXPORT_SYMBOL_GPL(__kvm_apic_update_irr);

-void kvm_apic_update_irr(struct kvm_vcpu *vcpu, u32 *pir)
+int kvm_apic_update_irr(struct kvm_vcpu *vcpu, u32 *pir)
 {
        struct kvm_lapic *apic = vcpu->arch.apic;

-       __kvm_apic_update_irr(pir, apic->regs);
+       return __kvm_apic_update_irr(pir, apic->regs);
 }
 EXPORT_SYMBOL_GPL(kvm_apic_update_irr);

@@ -376,7 +383,7 @@ static inline int apic_find_highest_irr(struct kvm_lapic 
*apic)
                return -1;

        if (apic->vcpu->arch.apicv_active)
-               kvm_x86_ops->sync_pir_to_irr(apic->vcpu);
+               kvm_x86_ops->sync_pir_to_irr(apic->vcpu, false);
        result = apic_search_irr(apic);

You have got the max_irr in sync_pir_to_irr. It seems the apic_search_irr() is redundant here.

        ASSERT(result == -1 || result >= 16);

I think the result must >= 32. But it seems this code exists when kvm first merging into kernel.


diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index f60d01c29d51..fc72828c3782 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -70,8 +70,8 @@ int kvm_lapic_reg_read(struct kvm_lapic *apic, u32 offset, 
int len,
 bool kvm_apic_match_dest(struct kvm_vcpu *vcpu, struct kvm_lapic *source,
                           int short_hand, unsigned int dest, int dest_mode);

-void __kvm_apic_update_irr(u32 *pir, void *regs);
-void kvm_apic_update_irr(struct kvm_vcpu *vcpu, u32 *pir);
+int __kvm_apic_update_irr(u32 *pir, void *regs);
+int kvm_apic_update_irr(struct kvm_vcpu *vcpu, u32 *pir);
 int kvm_apic_set_irq(struct kvm_vcpu *vcpu, struct kvm_lapic_irq *irq,
                     struct dest_map *dest_map);
 int kvm_apic_local_deliver(struct kvm_lapic *apic, int lvt_type);
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 9b4221471e3d..60e53fa2b554 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -4383,7 +4383,7 @@ static void svm_load_eoi_exitmap(struct kvm_vcpu *vcpu, 
u64 *eoi_exit_bitmap)
        return;
 }

-static void svm_sync_pir_to_irr(struct kvm_vcpu *vcpu)
+static void svm_sync_pir_to_irr(struct kvm_vcpu *vcpu, bool sync_rvi)
 {
        return;
 }
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 207b9aa32915..1edefab54d01 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -4852,17 +4852,6 @@ static void vmx_deliver_posted_interrupt(struct kvm_vcpu 
*vcpu, int vector)
                kvm_vcpu_kick(vcpu);
 }

-static void vmx_sync_pir_to_irr(struct kvm_vcpu *vcpu)
-{
-       struct vcpu_vmx *vmx = to_vmx(vcpu);
-
-       if (!pi_test_on(&vmx->pi_desc) ||
-           !pi_test_and_clear_on(&vmx->pi_desc))
-               return;
-
-       kvm_apic_update_irr(vcpu, vmx->pi_desc.pir);
-}
-
 /*
  * Set up the vmcs's constant host-state fields, i.e., host-state fields that
  * will not change in the lifetime of the guest.
@@ -8609,6 +8598,20 @@ static void vmx_hwapic_irr_update(struct kvm_vcpu *vcpu, 
int max_irr)
        }
 }

+static void vmx_sync_pir_to_irr(struct kvm_vcpu *vcpu, bool sync_rvi)
+{
+       struct vcpu_vmx *vmx = to_vmx(vcpu);
+       int max_irr;
+
+       if (!pi_test_on(&vmx->pi_desc) ||
+           !pi_test_and_clear_on(&vmx->pi_desc))
+               return;
+
+       max_irr = kvm_apic_update_irr(vcpu, vmx->pi_desc.pir);
+       if (sync_rvi)
+               vmx_hwapic_irr_update(vcpu, max_irr);
+}
+
 static void vmx_load_eoi_exitmap(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)
 {
        if (!kvm_vcpu_apicv_active(vcpu))
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 604cfbfc5bee..148e14fdc55d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2821,7 +2821,7 @@ static int kvm_vcpu_ioctl_get_lapic(struct kvm_vcpu *vcpu,
                                    struct kvm_lapic_state *s)
 {
        if (vcpu->arch.apicv_active)
-               kvm_x86_ops->sync_pir_to_irr(vcpu);
+               kvm_x86_ops->sync_pir_to_irr(vcpu, false);

        return kvm_apic_get_state(vcpu, s);
 }
@@ -6448,7 +6448,7 @@ static void vcpu_scan_ioapic(struct kvm_vcpu *vcpu)
                kvm_scan_ioapic_routes(vcpu, vcpu->arch.ioapic_handled_vectors);
        else {
                if (vcpu->arch.apicv_active)
-                       kvm_x86_ops->sync_pir_to_irr(vcpu);
+                       kvm_x86_ops->sync_pir_to_irr(vcpu, false);
                kvm_ioapic_scan_entry(vcpu, vcpu->arch.ioapic_handled_vectors);
        }
        bitmap_or((ulong *)eoi_exit_bitmap, vcpu->arch.ioapic_handled_vectors,
@@ -6611,8 +6611,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
                 * virtual interrupt delivery.
                 */
                if (vcpu->arch.apicv_active)
-                       kvm_x86_ops->hwapic_irr_update(vcpu,
-                               kvm_lapic_find_highest_irr(vcpu));
+                       kvm_x86_ops->sync_pir_to_irr(vcpu, true);
        }

        if (kvm_check_request(KVM_REQ_EVENT, vcpu) || req_int_win) {



--
Yang
Alibaba Cloud Computing

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