[patch 088/100] KVM: VMX: Update necessary state when guest enters long mode

Chris Wright
2009-04-23T07:55:00Z

[-- Attachment #1: kvm-vmx-update-necessary-state-when-guest-enters-long-mode.patch --]
[-- Type: text/plain, Size: 3054 bytes --]

-stable review patch. If anyone has any objections, please let us know.
---------------------

From: Amit Shah <amit.shah@redhat.com>

upstream commit: 401d10dee083bda281f2fdcdf654080313ba30ec

setup_msrs() should be called when entering long mode to save the
shadow state for the 64-bit guest state.

Using vmx_set_efer() in enter_lmode() removes some duplicated code
and also ensures we call setup_msrs(). We can safely pass the value
of shadow_efer to vmx_set_efer() as no other bits in the efer change
while enabling long mode (guest first sets EFER.LME, then sets CR0.PG
which causes a vmexit where we activate long mode).

With this fix, is_long_mode() can check for EFER.LMA set instead of
EFER.LME and 5e23049e86dd298b72e206b420513dbc3a240cd9 can be reverted.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
---
arch/x86/kvm/vmx.c | 54 +++++++++++++++++++++++------------------------------
1 file changed, 24 insertions(+), 30 deletions(-)

--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1433,6 +1433,29 @@ continue_rmode:
init_rmode(vcpu->kvm);
}

+static void vmx_set_efer(struct kvm_vcpu *vcpu, u64 efer)
+{
+ struct vcpu_vmx *vmx = to_vmx(vcpu);
+ struct kvm_msr_entry *msr = find_msr_entry(vmx, MSR_EFER);
+
+ vcpu->arch.shadow_efer = efer;
+ if (!msr)
+ return;
+ if (efer & EFER_LMA) {
+ vmcs_write32(VM_ENTRY_CONTROLS,
+ vmcs_read32(VM_ENTRY_CONTROLS) |
+ VM_ENTRY_IA32E_MODE);
+ msr->data = efer;
+ } else {
+ vmcs_write32(VM_ENTRY_CONTROLS,
+ vmcs_read32(VM_ENTRY_CONTROLS) &
+ ~VM_ENTRY_IA32E_MODE);
+
+ msr->data = efer & ~EFER_LME;
+ }
+ setup_msrs(vmx);
+}
+
#ifdef CONFIG_X86_64

static void enter_lmode(struct kvm_vcpu *vcpu)
@@ -1447,13 +1470,8 @@ static void enter_lmode(struct kvm_vcpu
(guest_tr_ar & ~AR_TYPE_MASK)
| AR_TYPE_BUSY_64_TSS);
}
-
vcpu->arch.shadow_efer |= EFER_LMA;
-
- find_msr_entry(to_vmx(vcpu), MSR_EFER)->data |= EFER_LMA | EFER_LME;
- vmcs_write32(VM_ENTRY_CONTROLS,
- vmcs_read32(VM_ENTRY_CONTROLS)
- | VM_ENTRY_IA32E_MODE);
+ vmx_set_efer(vcpu, vcpu->arch.shadow_efer);
}

static void exit_lmode(struct kvm_vcpu *vcpu)
@@ -1612,30 +1630,6 @@ static void vmx_set_cr4(struct kvm_vcpu
vmcs_writel(GUEST_CR4, hw_cr4);
}

-static void vmx_set_efer(struct kvm_vcpu *vcpu, u64 efer)
-{
- struct vcpu_vmx *vmx = to_vmx(vcpu);
- struct kvm_msr_entry *msr = find_msr_entry(vmx, MSR_EFER);
-
- vcpu->arch.shadow_efer = efer;
- if (!msr)
- return;
- if (efer & EFER_LMA) {
- vmcs_write32(VM_ENTRY_CONTROLS,
- vmcs_read32(VM_ENTRY_CONTROLS) |
- VM_ENTRY_IA32E_MODE);
- msr->data = efer;
-
- } else {
- vmcs_write32(VM_ENTRY_CONTROLS,
- vmcs_read32(VM_ENTRY_CONTROLS) &
- ~VM_ENTRY_IA32E_MODE);
-
- msr->data = efer & ~EFER_LME;
- }
- setup_msrs(vmx);
-}
-
static u64 vmx_get_segment_base(struct kvm_vcpu *vcpu, int seg)
{
struct kvm_vmx_segment_field *sf = &kvm_vmx_segment_fields[seg];