KVM: VMX: Fix commit which broke PML
I found PML was broken since below commit:
commit feda805fe7c4ed9cf78158e73b1218752e3b4314
Author: Xiao Guangrong <guangrong.xiao@linux.intel.com>
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@linux.intel.com>
[Rewrite to use vmcs_set_secondary_exec_control. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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.
Fixes: feda805fe7c4ed9cf78158e73b1218752e3b4314
Signed-off-by: Kai Huang <kai.huang@linux.intel.com>
[While at it, change a wrong ASSERT to an "if". The condition can happen
if creating the VCPU fails with ENOMEM. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 2ac11641..5eb56ed 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -4718,8 +4718,9 @@
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 @@
*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;
@@ -7817,18 +7818,15 @@
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);
- vmx->pml_pg = NULL;
-
- vmcs_clear_bits(SECONDARY_VM_EXEC_CONTROL, SECONDARY_EXEC_ENABLE_PML);
+ if (vmx->pml_pg) {
+ __free_page(vmx->pml_pg);
+ vmx->pml_pg = NULL;
+ }
}
static void vmx_flush_pml_buffer(struct kvm_vcpu *vcpu)
@@ -8706,7 +8704,7 @@
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 +8788,7 @@
* for the guest, etc.
*/
if (enable_pml) {
- err = vmx_enable_pml(vmx);
+ err = vmx_create_pml_buffer(vmx);
if (err)
goto free_vmcs;
}