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Subject[PATCH 12/23] KVM: SVM: merge update_cr0_intercept into svm_set_cr0
Date
The logic of update_cr0_intercept is pointlessly complicated.
All svm_set_cr0 is compute the effective cr0 and compare it with
the guest value.

Inlining the function and simplifying the condition
clarifies what it is doing.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/svm/svm.c | 54 +++++++++++++++++-------------------------
1 file changed, 22 insertions(+), 32 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index e7fcd92551e5..968d1a1f2927 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1718,37 +1718,10 @@ static void svm_set_gdt(struct kvm_vcpu *vcpu, struct desc_ptr *dt)
vmcb_mark_dirty(svm->vmcb, VMCB_DT);
}

-static void update_cr0_intercept(struct vcpu_svm *svm)
-{
- ulong gcr0;
- u64 *hcr0;
-
- /*
- * SEV-ES guests must always keep the CR intercepts cleared. CR
- * tracking is done using the CR write traps.
- */
- if (sev_es_guest(svm->vcpu.kvm))
- return;
-
- gcr0 = svm->vcpu.arch.cr0;
- hcr0 = &svm->vmcb->save.cr0;
- *hcr0 = (*hcr0 & ~SVM_CR0_SELECTIVE_MASK)
- | (gcr0 & SVM_CR0_SELECTIVE_MASK);
-
- vmcb_mark_dirty(svm->vmcb, VMCB_CR);
-
- if (gcr0 == *hcr0) {
- svm_clr_intercept(svm, INTERCEPT_CR0_READ);
- svm_clr_intercept(svm, INTERCEPT_CR0_WRITE);
- } else {
- svm_set_intercept(svm, INTERCEPT_CR0_READ);
- svm_set_intercept(svm, INTERCEPT_CR0_WRITE);
- }
-}
-
void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
{
struct vcpu_svm *svm = to_svm(vcpu);
+ u64 hcr0 = cr0;

#ifdef CONFIG_X86_64
if (vcpu->arch.efer & EFER_LME && !vcpu->arch.guest_state_protected) {
@@ -1766,7 +1739,7 @@ void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
vcpu->arch.cr0 = cr0;

if (!npt_enabled)
- cr0 |= X86_CR0_PG | X86_CR0_WP;
+ hcr0 |= X86_CR0_PG | X86_CR0_WP;

/*
* re-enable caching here because the QEMU bios
@@ -1774,10 +1747,27 @@ void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
* reboot
*/
if (kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_CD_NW_CLEARED))
- cr0 &= ~(X86_CR0_CD | X86_CR0_NW);
- svm->vmcb->save.cr0 = cr0;
+ hcr0 &= ~(X86_CR0_CD | X86_CR0_NW);
+
+ svm->vmcb->save.cr0 = hcr0;
vmcb_mark_dirty(svm->vmcb, VMCB_CR);
- update_cr0_intercept(svm);
+
+ /*
+ * SEV-ES guests must always keep the CR intercepts cleared. CR
+ * tracking is done using the CR write traps.
+ */
+ if (sev_es_guest(svm->vcpu.kvm))
+ return;
+
+ if (hcr0 == cr0) {
+ /* Selective CR0 write remains on. */
+ svm_clr_intercept(svm, INTERCEPT_CR0_READ);
+ svm_clr_intercept(svm, INTERCEPT_CR0_WRITE);
+ } else {
+ svm_set_intercept(svm, INTERCEPT_CR0_READ);
+ svm_set_intercept(svm, INTERCEPT_CR0_WRITE);
+ }
+
}

static bool svm_is_valid_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
--
2.26.2

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