[PATCH 29/31] KVM: SVM: remove selective CR0 comment

From: Avi Kivity
Date: Mon Apr 21 2008 - 06:40:20 EST


From: Joerg Roedel <joerg.roedel@xxxxxxx>

There is not selective cr0 intercept bug. The code in the comment sets the
CR0.PG bit. But KVM sets the CR4.PG bit for SVM always to implement the paged
real mode. So the 'mov %eax,%cr0' instruction does not change the CR0.PG bit.
Selective CR0 intercepts only occur when a bit is actually changed. So its the
right behavior that there is no intercept on this instruction.

Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx>
Signed-off-by: Avi Kivity <avi@xxxxxxxxxxxx>
---
arch/x86/kvm/svm.c | 11 -----------
1 files changed, 0 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index d643605..89e0be2 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -513,17 +513,6 @@ static void init_vmcb(struct vcpu_svm *svm)
control->intercept = (1ULL << INTERCEPT_INTR) |
(1ULL << INTERCEPT_NMI) |
(1ULL << INTERCEPT_SMI) |
- /*
- * selective cr0 intercept bug?
- * 0: 0f 22 d8 mov %eax,%cr3
- * 3: 0f 20 c0 mov %cr0,%eax
- * 6: 0d 00 00 00 80 or $0x80000000,%eax
- * b: 0f 22 c0 mov %eax,%cr0
- * set cr3 ->interception
- * get cr0 ->interception
- * set cr0 -> no interception
- */
- /* (1ULL << INTERCEPT_SELECTIVE_CR0) | */
(1ULL << INTERCEPT_CPUID) |
(1ULL << INTERCEPT_INVD) |
(1ULL << INTERCEPT_HLT) |
--
1.5.5

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