Re: [PATCH v5 2/4] KVM: async_pf: Add L1 guest async_pf #PF vmexit handler
2017-06-27 21:30 GMT+08:00 Paolo Bonzini :
>
>
> On 27/06/2017 03:46, Wanpeng Li wrote:
>> From: Wanpeng Li
>>
>> This patch adds the L1 guest async page fault #PF vmexit handler, such
>> #PF is converted into vmexit from L2 to L1 on #PF which is then handled
>> by L1 similar to ordinary async page fault.
>>
>> Cc: Paolo Bonzini
>> Cc: Radim Krčmář
>> Signed-off-by: Wanpeng Li
>> ---
>> arch/x86/kvm/vmx.c | 34 --
>> 1 file changed, 28 insertions(+), 6 deletions(-)
>>
>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
>> index df825bb..f533cc1 100644
>> --- a/arch/x86/kvm/vmx.c
>> +++ b/arch/x86/kvm/vmx.c
>> @@ -616,6 +616,7 @@ struct vcpu_vmx {
>> bool emulation_required;
>>
>> u32 exit_reason;
>> + u32 apf_reason;
>
> Can you instead of move vcpu_svm's apf_reason field to kvm_vcpu_arch?
> (e.g. vcpu->arch.apf.host_apf_reason)?
Agreed.
>
>> /* Posted interrupt descriptor */
>> struct pi_desc pi_desc;
>> @@ -5648,14 +5649,31 @@ static int handle_exception(struct kvm_vcpu *vcpu)
>> }
>>
>> if (is_page_fault(intr_info)) {
>> - /* EPT won't cause page fault directly */
>> - BUG_ON(enable_ept);
>> cr2 = vmcs_readl(EXIT_QUALIFICATION);
>> - trace_kvm_page_fault(cr2, error_code);
>> + switch (vmx->apf_reason) {
>> + default:
>> + /* EPT won't cause page fault directly */
>> + BUG_ON(enable_ept);
>> + trace_kvm_page_fault(cr2, error_code);
>>
>> - if (kvm_event_needs_reinjection(vcpu))
>> - kvm_mmu_unprotect_page_virt(vcpu, cr2);
>> - return kvm_mmu_page_fault(vcpu, cr2, error_code, NULL, 0);
>> + if (kvm_event_needs_reinjection(vcpu))
>> + kvm_mmu_unprotect_page_virt(vcpu, cr2);
>> + return kvm_mmu_page_fault(vcpu, cr2, error_code, NULL,
>> 0);
>> + break;
>> + case KVM_PV_REASON_PAGE_NOT_PRESENT:
>> + vmx->apf_reason = 0;
>> + local_irq_disable();
>> + kvm_async_pf_task_wait(cr2);
>> + local_irq_enable();
>> + break;
>> + case KVM_PV_REASON_PAGE_READY:
>> + vmx->apf_reason = 0;
>> + local_irq_disable();
>> + kvm_async_pf_task_wake(cr2);
>> + local_irq_enable();
>> + break;
>> + }
>> + return 0;
>> }
>
>
> This code can be moved to a common function
>
> int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code,
> u64 fault_address);
>
> in mmu.c. It can be used by vmx.c here and in svm.c's pf_interception.
>
> You can change "enable_ept" to "tdp_enabled" (but please make that a
> WARN_ON_ONCE, too).
Agreed. :)
Regards,
Wanpeng Li
Re: [PATCH v5 2/4] KVM: async_pf: Add L1 guest async_pf #PF vmexit handler
On 27/06/2017 03:46, Wanpeng Li wrote:
> From: Wanpeng Li
>
> This patch adds the L1 guest async page fault #PF vmexit handler, such
> #PF is converted into vmexit from L2 to L1 on #PF which is then handled
> by L1 similar to ordinary async page fault.
>
> Cc: Paolo Bonzini
> Cc: Radim Krčmář
> Signed-off-by: Wanpeng Li
> ---
> arch/x86/kvm/vmx.c | 34 --
> 1 file changed, 28 insertions(+), 6 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index df825bb..f533cc1 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -616,6 +616,7 @@ struct vcpu_vmx {
> bool emulation_required;
>
> u32 exit_reason;
> + u32 apf_reason;
Can you instead of move vcpu_svm's apf_reason field to kvm_vcpu_arch?
(e.g. vcpu->arch.apf.host_apf_reason)?
> /* Posted interrupt descriptor */
> struct pi_desc pi_desc;
> @@ -5648,14 +5649,31 @@ static int handle_exception(struct kvm_vcpu *vcpu)
> }
>
> if (is_page_fault(intr_info)) {
> - /* EPT won't cause page fault directly */
> - BUG_ON(enable_ept);
> cr2 = vmcs_readl(EXIT_QUALIFICATION);
> - trace_kvm_page_fault(cr2, error_code);
> + switch (vmx->apf_reason) {
> + default:
> + /* EPT won't cause page fault directly */
> + BUG_ON(enable_ept);
> + trace_kvm_page_fault(cr2, error_code);
>
> - if (kvm_event_needs_reinjection(vcpu))
> - kvm_mmu_unprotect_page_virt(vcpu, cr2);
> - return kvm_mmu_page_fault(vcpu, cr2, error_code, NULL, 0);
> + if (kvm_event_needs_reinjection(vcpu))
> + kvm_mmu_unprotect_page_virt(vcpu, cr2);
> + return kvm_mmu_page_fault(vcpu, cr2, error_code, NULL,
> 0);
> + break;
> + case KVM_PV_REASON_PAGE_NOT_PRESENT:
> + vmx->apf_reason = 0;
> + local_irq_disable();
> + kvm_async_pf_task_wait(cr2);
> + local_irq_enable();
> + break;
> + case KVM_PV_REASON_PAGE_READY:
> + vmx->apf_reason = 0;
> + local_irq_disable();
> + kvm_async_pf_task_wake(cr2);
> + local_irq_enable();
> + break;
> + }
> + return 0;
> }
This code can be moved to a common function
int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code,
u64 fault_address);
in mmu.c. It can be used by vmx.c here and in svm.c's pf_interception.
You can change "enable_ept" to "tdp_enabled" (but please make that a
WARN_ON_ONCE, too).
Thanks,
Paolo
[PATCH v5 2/4] KVM: async_pf: Add L1 guest async_pf #PF vmexit handler
From: Wanpeng Li
This patch adds the L1 guest async page fault #PF vmexit handler, such
#PF is converted into vmexit from L2 to L1 on #PF which is then handled
by L1 similar to ordinary async page fault.
Cc: Paolo Bonzini
Cc: Radim Krčmář
Signed-off-by: Wanpeng Li
---
arch/x86/kvm/vmx.c | 34 --
1 file changed, 28 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index df825bb..f533cc1 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -616,6 +616,7 @@ struct vcpu_vmx {
bool emulation_required;
u32 exit_reason;
+ u32 apf_reason;
/* Posted interrupt descriptor */
struct pi_desc pi_desc;
@@ -5648,14 +5649,31 @@ static int handle_exception(struct kvm_vcpu *vcpu)
}
if (is_page_fault(intr_info)) {
- /* EPT won't cause page fault directly */
- BUG_ON(enable_ept);
cr2 = vmcs_readl(EXIT_QUALIFICATION);
- trace_kvm_page_fault(cr2, error_code);
+ switch (vmx->apf_reason) {
+ default:
+ /* EPT won't cause page fault directly */
+ BUG_ON(enable_ept);
+ trace_kvm_page_fault(cr2, error_code);
- if (kvm_event_needs_reinjection(vcpu))
- kvm_mmu_unprotect_page_virt(vcpu, cr2);
- return kvm_mmu_page_fault(vcpu, cr2, error_code, NULL, 0);
+ if (kvm_event_needs_reinjection(vcpu))
+ kvm_mmu_unprotect_page_virt(vcpu, cr2);
+ return kvm_mmu_page_fault(vcpu, cr2, error_code, NULL,
0);
+ break;
+ case KVM_PV_REASON_PAGE_NOT_PRESENT:
+ vmx->apf_reason = 0;
+ local_irq_disable();
+ kvm_async_pf_task_wait(cr2);
+ local_irq_enable();
+ break;
+ case KVM_PV_REASON_PAGE_READY:
+ vmx->apf_reason = 0;
+ local_irq_disable();
+ kvm_async_pf_task_wake(cr2);
+ local_irq_enable();
+ break;
+ }
+ return 0;
}
ex_no = intr_info & INTR_INFO_VECTOR_MASK;
@@ -8602,6 +8620,10 @@ static void vmx_complete_atomic_exit(struct vcpu_vmx
*vmx)
vmx->exit_intr_info = vmcs_read32(VM_EXIT_INTR_INFO);
exit_intr_info = vmx->exit_intr_info;
+ /* if exit due to PF check for async PF */
+ if (is_page_fault(exit_intr_info))
+ vmx->apf_reason = kvm_read_and_reset_pf_reason();
+
/* Handle machine checks before interrupts are enabled */
if (is_machine_check(exit_intr_info))
kvm_machine_check();
--
2.7.4
