Re: [PATCH v5 05/13] X86/nVMX: handle_vmptrld: Use kvm_vcpu_map when copying VMCS12 from guest memory

[Konrad Rzeszutek Wilk]

On Wed, Jan 09, 2019 at 10:42:05AM +0100, KarimAllah Ahmed wrote:
> Use kvm_vcpu_map to the map the VMCS12 from guest memory because
> kvm_vcpu_gpa_to_page() and kmap() will only work for guest memory that has
> a "struct page".
> 
> Signed-off-by: KarimAllah Ahmed 

Reviewed-by: Konrad Rzeszutek Wilk 
> ---
> v4 -> v5:
> - Switch to the new guest mapping API instead of reading directly from
>   guest.
> - unmap with dirty flag
> v3 -> v4:
> - Return VMXERR_VMPTRLD_INCORRECT_VMCS_REVISION_ID on failure (jmattson@)
> v1 -> v2:
> - Massage commit message a bit.
> ---
>  arch/x86/kvm/vmx/nested.c | 15 +++
>  1 file changed, 7 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index 536468a..5602b0c 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -4521,11 +4521,10 @@ static int handle_vmptrld(struct kvm_vcpu *vcpu)
>   return 1;
>  
>   if (vmx->nested.current_vmptr != vmptr) {
> + struct kvm_host_map map;
>   struct vmcs12 *new_vmcs12;
> - struct page *page;
>  
> - page = kvm_vcpu_gpa_to_page(vcpu, vmptr);
> - if (is_error_page(page)) {
> + if (kvm_vcpu_map(vcpu, gpa_to_gfn(vmptr), &map)) {
>   /*
>* Reads from an unbacked page return all 1s,
>* which means that the 32 bits located at the
> @@ -4536,12 +4535,13 @@ static int handle_vmptrld(struct kvm_vcpu *vcpu)
>   VMXERR_VMPTRLD_INCORRECT_VMCS_REVISION_ID);
>   return kvm_skip_emulated_instruction(vcpu);
>   }
> - new_vmcs12 = kmap(page);
> +
> + new_vmcs12 = map.hva;
> +
>   if (new_vmcs12->hdr.revision_id != VMCS12_REVISION ||
>   (new_vmcs12->hdr.shadow_vmcs &&
>!nested_cpu_has_vmx_shadow_vmcs(vcpu))) {
> - kunmap(page);
> - kvm_release_page_clean(page);
> + kvm_vcpu_unmap(&map, false);
>   return nested_vmx_failValid(vcpu,
>   VMXERR_VMPTRLD_INCORRECT_VMCS_REVISION_ID);
>   }
> @@ -4553,8 +4553,7 @@ static int handle_vmptrld(struct kvm_vcpu *vcpu)
>* cached.
>*/
>   memcpy(vmx->nested.cached_vmcs12, new_vmcs12, VMCS12_SIZE);
> - kunmap(page);
> - kvm_release_page_clean(page);
> + kvm_vcpu_unmap(&map, false);
>  
>   set_current_vmptr(vmx, vmptr);
>   }
> -- 
> 2.7.4
> 

[PATCH v5 05/13] X86/nVMX: handle_vmptrld: Use kvm_vcpu_map when copying VMCS12 from guest memory

[KarimAllah Ahmed]

Use kvm_vcpu_map to the map the VMCS12 from guest memory because
kvm_vcpu_gpa_to_page() and kmap() will only work for guest memory that has
a "struct page".

Signed-off-by: KarimAllah Ahmed 
---
v4 -> v5:
- Switch to the new guest mapping API instead of reading directly from
  guest.
- unmap with dirty flag
v3 -> v4:
- Return VMXERR_VMPTRLD_INCORRECT_VMCS_REVISION_ID on failure (jmattson@)
v1 -> v2:
- Massage commit message a bit.
---
 arch/x86/kvm/vmx/nested.c | 15 +++
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 536468a..5602b0c 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -4521,11 +4521,10 @@ static int handle_vmptrld(struct kvm_vcpu *vcpu)
return 1;
 
if (vmx->nested.current_vmptr != vmptr) {
+   struct kvm_host_map map;
struct vmcs12 *new_vmcs12;
-   struct page *page;
 
-   page = kvm_vcpu_gpa_to_page(vcpu, vmptr);
-   if (is_error_page(page)) {
+   if (kvm_vcpu_map(vcpu, gpa_to_gfn(vmptr), &map)) {
/*
 * Reads from an unbacked page return all 1s,
 * which means that the 32 bits located at the
@@ -4536,12 +4535,13 @@ static int handle_vmptrld(struct kvm_vcpu *vcpu)
VMXERR_VMPTRLD_INCORRECT_VMCS_REVISION_ID);
return kvm_skip_emulated_instruction(vcpu);
}
-   new_vmcs12 = kmap(page);
+
+   new_vmcs12 = map.hva;
+
if (new_vmcs12->hdr.revision_id != VMCS12_REVISION ||
(new_vmcs12->hdr.shadow_vmcs &&
 !nested_cpu_has_vmx_shadow_vmcs(vcpu))) {
-   kunmap(page);
-   kvm_release_page_clean(page);
+   kvm_vcpu_unmap(&map, false);
return nested_vmx_failValid(vcpu,
VMXERR_VMPTRLD_INCORRECT_VMCS_REVISION_ID);
}
@@ -4553,8 +4553,7 @@ static int handle_vmptrld(struct kvm_vcpu *vcpu)
 * cached.
 */
memcpy(vmx->nested.cached_vmcs12, new_vmcs12, VMCS12_SIZE);
-   kunmap(page);
-   kvm_release_page_clean(page);
+   kvm_vcpu_unmap(&map, false);
 
set_current_vmptr(vmx, vmptr);
}
-- 
2.7.4