Hi Paolo,
Thanks for applying! I am really sorry that I forgot to delete the line
that clears SECONDARY_EXEC_ENABLE_PML bit in vmx_disable_pml, which is
renamed to vmx_destroy_pml_buffer now.
It won't impact functionality but to make the function consistent, would
you also do below? Sorry for such negligence!
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 89f4fa2..ef4ca76 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -7826,8 +7826,6 @@ static void vmx_destroy_pml_buffer(struct vcpu_vmx
*vmx)
ASSERT(vmx->pml_pg);
__free_page(vmx->pml_pg);
vmx->pml_pg = NULL;
-
- vmcs_clear_bits(SECONDARY_VM_EXEC_CONTROL,
SECONDARY_EXEC_ENABLE_PML);
}
Thanks,
-Kai
On 11/04/2015 08:00 PM, Paolo Bonzini wrote:
On 04/11/2015 06:46, Kai Huang wrote:
I found PML was broken since below commit:
commit feda805fe7c4ed9cf78158e73b1218752e3b4314
Author: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>
Date: Wed Sep 9 14:05:55 2015 +0800
KVM: VMX: unify SECONDARY_VM_EXEC_CONTROL update
Unify the update in vmx_cpuid_update()
Signed-off-by: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>
[Rewrite to use vmcs_set_secondary_exec_control. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
The reason is in above commit vmx_cpuid_update calls vmx_secondary_exec_control,
in which currently SECONDARY_EXEC_ENABLE_PML bit is cleared unconditionally (as
PML is enabled in creating vcpu). Therefore if vcpu_cpuid_update is called after
vcpu is created, PML will be disabled unexpectedly while log-dirty code still
thinks PML is used.
Fix this by clearing SECONDARY_EXEC_ENABLE_PML in vmx_secondary_exec_control
only when PML is not supported or not enabled (!enable_pml). This is more
reasonable as PML is currently either always enabled or disabled. With this
explicit updating SECONDARY_EXEC_ENABLE_PML in vmx_enable{disable}_pml is not
needed so also rename vmx_enable{disable}_pml to vmx_create{destroy}_pml_buffer.
Signed-off-by: Kai Huang <kai.huang@xxxxxxxxxxxxxxx>
---
v1->v2: Fix this by following Paolo's suggestion. It's better to not to clear
SECONDARY_EXEC_ENABLE_PML in vmx_secondary_exec_control unconditionally but only
clear it when PML is not supported or enabled.
---
arch/x86/kvm/vmx.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 2ac11641..89f4fa2 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -4718,8 +4718,9 @@ static u32 vmx_secondary_exec_control(struct vcpu_vmx *vmx)
a current VMCS12
*/
exec_control &= ~SECONDARY_EXEC_SHADOW_VMCS;
- /* PML is enabled/disabled in creating/destorying vcpu */
- exec_control &= ~SECONDARY_EXEC_ENABLE_PML;
+
+ if (!enable_pml)
+ exec_control &= ~SECONDARY_EXEC_ENABLE_PML;
/* Currently, we allow L1 guest to directly run pcommit instruction. */
exec_control &= ~SECONDARY_EXEC_PCOMMIT;
@@ -7804,7 +7805,7 @@ static void vmx_get_exit_info(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2)
*info2 = vmcs_read32(VM_EXIT_INTR_INFO);
}
-static int vmx_enable_pml(struct vcpu_vmx *vmx)
+static int vmx_create_pml_buffer(struct vcpu_vmx *vmx)
{
struct page *pml_pg;
@@ -7817,12 +7818,10 @@ static int vmx_enable_pml(struct vcpu_vmx *vmx)
vmcs_write64(PML_ADDRESS, page_to_phys(vmx->pml_pg));
vmcs_write16(GUEST_PML_INDEX, PML_ENTITY_NUM - 1);
- vmcs_set_bits(SECONDARY_VM_EXEC_CONTROL, SECONDARY_EXEC_ENABLE_PML);
-
return 0;
}
-static void vmx_disable_pml(struct vcpu_vmx *vmx)
+static void vmx_destroy_pml_buffer(struct vcpu_vmx *vmx)
{
ASSERT(vmx->pml_pg);
__free_page(vmx->pml_pg);
@@ -8706,7 +8705,7 @@ static void vmx_free_vcpu(struct kvm_vcpu *vcpu)
struct vcpu_vmx *vmx = to_vmx(vcpu);
if (enable_pml)
- vmx_disable_pml(vmx);
+ vmx_destroy_pml_buffer(vmx);
free_vpid(vmx->vpid);
leave_guest_mode(vcpu);
vmx_load_vmcs01(vcpu);
@@ -8790,7 +8789,7 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
* for the guest, etc.
*/
if (enable_pml) {
- err = vmx_enable_pml(vmx);
+ err = vmx_create_pml_buffer(vmx);
if (err)
goto free_vmcs;
}
Applied, thanks!
Paolo
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