[PATCH 1/3] KVM: Fix mov cr0 #GP at wrong instruction

Avi Kivity
2010-06-10T14:02:20Z

arch/x86/kvm/svm.c | 2 +-
arch/x86/kvm/vmx.c | 13 +++++++++++--
arch/x86/kvm/x86.c | 12 +++---------
4 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 0cd0f29..f0683c8 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -596,7 +596,7 @@ int kvm_load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector, int seg);
int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason,
bool has_error_code, u32 error_code);

-void kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0);
+int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0);
void kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3);
void kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4);
void kvm_set_cr8(struct kvm_vcpu *vcpu, unsigned long cr8);
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 2ae0c39..6d1616d 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -807,7 +807,7 @@ static void init_vmcb(struct vcpu_svm *svm)
* svm_set_cr0() sets PG and WP and clears NW and CD on save->cr0.
*/
svm->vcpu.arch.cr0 = X86_CR0_NW | X86_CR0_CD | X86_CR0_ET;
- kvm_set_cr0(&svm->vcpu, svm->vcpu.arch.cr0);
+ (void)kvm_set_cr0(&svm->vcpu, svm->vcpu.arch.cr0);

save->cr4 = X86_CR4_PAE;
/* rdx = ?? */
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 7fa6ea7..a6a5121 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3158,11 +3158,20 @@ vmx_patch_hypercall(struct kvm_vcpu *vcpu, unsigned char *hypercall)
hypercall[2] = 0xc1;
}

+static void complete_insn_gp(struct kvm_vcpu *vcpu, int err)
+{
+ if (err)
+ kvm_inject_gp(vcpu, 0);
+ else
+ skip_emulated_instruction(vcpu);
+}
+
static int handle_cr(struct kvm_vcpu *vcpu)
{
unsigned long exit_qualification, val;
int cr;
int reg;
+ int err;

exit_qualification = vmcs_readl(EXIT_QUALIFICATION);
cr = exit_qualification & 15;
@@ -3173,8 +3182,8 @@ static int handle_cr(struct kvm_vcpu *vcpu)
trace_kvm_cr_write(cr, val);
switch (cr) {
case 0:
- kvm_set_cr0(vcpu, val);
- skip_emulated_instruction(vcpu);
+ err = kvm_set_cr0(vcpu, val);
+ complete_insn_gp(vcpu, err);
return 1;
case 3:
kvm_set_cr3(vcpu, val);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5fa8684..72df8fd 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -417,7 +417,7 @@ out:
return changed;
}

-static int __kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
+int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
{
unsigned long old_cr0 = kvm_read_cr0(vcpu);
unsigned long update_bits = X86_CR0_PG | X86_CR0_WP |
@@ -460,17 +460,11 @@ static int __kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
kvm_mmu_reset_context(vcpu);
return 0;
}
-
-void kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
-{
- if (__kvm_set_cr0(vcpu, cr0))
- kvm_inject_gp(vcpu, 0);
-}
EXPORT_SYMBOL_GPL(kvm_set_cr0);

void kvm_lmsw(struct kvm_vcpu *vcpu, unsigned long msw)
{
- kvm_set_cr0(vcpu, kvm_read_cr0_bits(vcpu, ~0x0eul) | (msw & 0x0f));
+ (void)kvm_set_cr0(vcpu, kvm_read_cr0_bits(vcpu, ~0x0eul) | (msw & 0x0f));
}
EXPORT_SYMBOL_GPL(kvm_lmsw);

@@ -3652,7 +3646,7 @@ static int emulator_set_cr(int cr, unsigned long val, struct kvm_vcpu *vcpu)

switch (cr) {
case 0:
- res = __kvm_set_cr0(vcpu, mk_cr_64(kvm_read_cr0(vcpu), val));
+ res = kvm_set_cr0(vcpu, mk_cr_64(kvm_read_cr0(vcpu), val));
break;
case 2:
vcpu->arch.cr2 = val;
--
1.7.1