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Subject[PATCH 19/28] KVM: nSVM: extract svm_set_gif
Date
Extract the code that is needed to implement CLGI and STGI,
so that we can run it from VMRUN and vmexit (and in the future,
KVM_SET_NESTED_STATE). Skip the request for KVM_REQ_EVENT unless needed,
subsuming the evaluate_pending_interrupts optimization that is found
in enter_svm_guest_mode.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/irq.c | 1 +
arch/x86/kvm/svm/nested.c | 22 ++---------------
arch/x86/kvm/svm/svm.c | 51 ++++++++++++++++++++++++++-------------
arch/x86/kvm/svm/svm.h | 1 +
4 files changed, 38 insertions(+), 37 deletions(-)

diff --git a/arch/x86/kvm/irq.c b/arch/x86/kvm/irq.c
index 54f7ea68083b..99d118ffc67d 100644
--- a/arch/x86/kvm/irq.c
+++ b/arch/x86/kvm/irq.c
@@ -83,6 +83,7 @@ int kvm_cpu_has_injectable_intr(struct kvm_vcpu *v)

return kvm_apic_has_interrupt(v) != -1; /* LAPIC */
}
+EXPORT_SYMBOL_GPL(kvm_cpu_has_injectable_intr);

/*
* check if there is pending interrupt without
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 4355286b2726..f5956ecfeeac 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -333,10 +333,6 @@ static void nested_prepare_vmcb_control(struct vcpu_svm *svm)
void enter_svm_guest_mode(struct vcpu_svm *svm, u64 vmcb_gpa,
struct vmcb *nested_vmcb)
{
- bool evaluate_pending_interrupts =
- is_intercept(svm, INTERCEPT_VINTR) ||
- is_intercept(svm, INTERCEPT_IRET);
-
svm->nested.vmcb = vmcb_gpa;
if (kvm_get_rflags(&svm->vcpu) & X86_EFLAGS_IF)
svm->vcpu.arch.hflags |= HF_HIF_MASK;
@@ -347,21 +343,7 @@ void enter_svm_guest_mode(struct vcpu_svm *svm, u64 vmcb_gpa,
nested_prepare_vmcb_save(svm, nested_vmcb);
nested_prepare_vmcb_control(svm);

- /*
- * If L1 had a pending IRQ/NMI before executing VMRUN,
- * which wasn't delivered because it was disallowed (e.g.
- * interrupts disabled), L0 needs to evaluate if this pending
- * event should cause an exit from L2 to L1 or be delivered
- * directly to L2.
- *
- * Usually this would be handled by the processor noticing an
- * IRQ/NMI window request. However, VMRUN can unblock interrupts
- * by implicitly setting GIF, so force L0 to perform pending event
- * evaluation by requesting a KVM_REQ_EVENT.
- */
- enable_gif(svm);
- if (unlikely(evaluate_pending_interrupts))
- kvm_make_request(KVM_REQ_EVENT, &svm->vcpu);
+ svm_set_gif(svm, true);
}

int nested_svm_vmrun(struct vcpu_svm *svm)
@@ -505,7 +487,7 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
svm->vcpu.arch.mp_state = KVM_MP_STATE_RUNNABLE;

/* Give the current vmcb to the guest */
- disable_gif(svm);
+ svm_set_gif(svm, false);

nested_vmcb->save.es = vmcb->save.es;
nested_vmcb->save.cs = vmcb->save.cs;
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 0654c5672b1a..df3fcaa827c7 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1981,6 +1981,38 @@ static int vmrun_interception(struct vcpu_svm *svm)
return nested_svm_vmrun(svm);
}

+void svm_set_gif(struct vcpu_svm *svm, bool value)
+{
+ if (value) {
+ /*
+ * If VGIF is enabled, the STGI intercept is only added to
+ * detect the opening of the SMI/NMI window; remove it now.
+ * Likewise, clear the VINTR intercept, we will set it
+ * again while processing KVM_REQ_EVENT if needed.
+ */
+ if (vgif_enabled(svm))
+ clr_intercept(svm, INTERCEPT_STGI);
+ if (is_intercept(svm, SVM_EXIT_VINTR))
+ svm_clear_vintr(svm);
+
+ enable_gif(svm);
+ if (svm->vcpu.arch.smi_pending ||
+ svm->vcpu.arch.nmi_pending ||
+ kvm_cpu_has_injectable_intr(&svm->vcpu))
+ kvm_make_request(KVM_REQ_EVENT, &svm->vcpu);
+ } else {
+ disable_gif(svm);
+
+ /*
+ * After a CLGI no interrupts should come. But if vGIF is
+ * in use, we still rely on the VINTR intercept (rather than
+ * STGI) to detect an open interrupt window.
+ */
+ if (!vgif_enabled(svm))
+ svm_clear_vintr(svm);
+ }
+}
+
static int stgi_interception(struct vcpu_svm *svm)
{
int ret;
@@ -1988,18 +2020,8 @@ static int stgi_interception(struct vcpu_svm *svm)
if (nested_svm_check_permissions(svm))
return 1;

- /*
- * If VGIF is enabled, the STGI intercept is only added to
- * detect the opening of the SMI/NMI window; remove it now.
- */
- if (vgif_enabled(svm))
- clr_intercept(svm, INTERCEPT_STGI);
-
ret = kvm_skip_emulated_instruction(&svm->vcpu);
- kvm_make_request(KVM_REQ_EVENT, &svm->vcpu);
-
- enable_gif(svm);
-
+ svm_set_gif(svm, true);
return ret;
}

@@ -2011,12 +2033,7 @@ static int clgi_interception(struct vcpu_svm *svm)
return 1;

ret = kvm_skip_emulated_instruction(&svm->vcpu);
-
- disable_gif(svm);
-
- /* After a CLGI no interrupts should come */
- svm_clear_vintr(svm);
-
+ svm_set_gif(svm, false);
return ret;
}

diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 7e79f0af1204..10b7b55720a0 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -357,6 +357,7 @@ void disable_nmi_singlestep(struct vcpu_svm *svm);
bool svm_smi_blocked(struct kvm_vcpu *vcpu);
bool svm_nmi_blocked(struct kvm_vcpu *vcpu);
bool svm_interrupt_blocked(struct kvm_vcpu *vcpu);
+void svm_set_gif(struct vcpu_svm *svm, bool value);

/* nested.c */

--
2.26.2

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