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Subject[PATCH 1/4] KVM: nSVM: do not change host intercepts while nested VM is running
Date
Instead of touching the host intercepts so that the bitwise OR in
recalc_intercepts just works, mask away uninteresting intercepts
directly in recalc_intercepts.

This is cleaner and keeps the logic in one place even for intercepts
that can change even while L2 is running.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/svm.c | 31 ++++++++++++++++++-------------
1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 247e31d21b96..14cb5c194008 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -519,10 +519,24 @@ static void recalc_intercepts(struct vcpu_svm *svm)
h = &svm->nested.hsave->control;
g = &svm->nested;

- c->intercept_cr = h->intercept_cr | g->intercept_cr;
- c->intercept_dr = h->intercept_dr | g->intercept_dr;
- c->intercept_exceptions = h->intercept_exceptions | g->intercept_exceptions;
- c->intercept = h->intercept | g->intercept;
+ c->intercept_cr = h->intercept_cr;
+ c->intercept_dr = h->intercept_dr;
+ c->intercept_exceptions = h->intercept_exceptions;
+ c->intercept = h->intercept;
+
+ if (svm->vcpu.arch.hflags & HF_VINTR_MASK) {
+ /* We only want the cr8 intercept bits of L1 */
+ c->intercept_cr &= ~(1U << INTERCEPT_CR8_READ);
+ c->intercept_cr &= ~(1U << INTERCEPT_CR8_WRITE);
+ }
+
+ /* We don't want to see VMMCALLs from a nested guest */
+ c->intercept &= ~(1ULL << INTERCEPT_VMMCALL);
+
+ c->intercept_cr |= g->intercept_cr;
+ c->intercept_dr |= g->intercept_dr;
+ c->intercept_exceptions |= g->intercept_exceptions;
+ c->intercept |= g->intercept;
}

static inline struct vmcb *get_host_vmcb(struct vcpu_svm *svm)
@@ -3590,15 +3604,6 @@ static void enter_svm_guest_mode(struct vcpu_svm *svm, u64 vmcb_gpa,
else
svm->vcpu.arch.hflags &= ~HF_VINTR_MASK;

- if (svm->vcpu.arch.hflags & HF_VINTR_MASK) {
- /* We only want the cr8 intercept bits of the guest */
- clr_cr_intercept(svm, INTERCEPT_CR8_READ);
- clr_cr_intercept(svm, INTERCEPT_CR8_WRITE);
- }
-
- /* We don't want to see VMMCALLs from a nested guest */
- clr_intercept(svm, INTERCEPT_VMMCALL);
-
svm->vcpu.arch.tsc_offset += nested_vmcb->control.tsc_offset;
svm->vmcb->control.tsc_offset = svm->vcpu.arch.tsc_offset;

--
1.8.3.1

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