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Subject[PATCH v4 02/14] X86/nVMX: handle_vmptrld: Copy the VMCS12 directly from guest memory
Date
Copy the VMCS12 directly from guest memory instead of the map->copy->unmap
sequence. This also avoids using kvm_vcpu_gpa_to_page() and kmap() which
assumes that there is a "struct page" for guest memory.

Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
---
v3 -> v4:
- Return VMXERR_VMPTRLD_INCORRECT_VMCS_REVISION_ID on failure (jmattson@)
v1 -> v2:
- Massage commit message a bit.
---
arch/x86/kvm/vmx.c | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index b84f230..75817cb 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -9301,20 +9301,22 @@ static int handle_vmptrld(struct kvm_vcpu *vcpu)
return 1;

if (vmx->nested.current_vmptr != vmptr) {
- struct vmcs12 *new_vmcs12;
- struct page *page;
- page = kvm_vcpu_gpa_to_page(vcpu, vmptr);
- if (is_error_page(page))
- return nested_vmx_failInvalid(vcpu);
+ struct vmcs12 *new_vmcs12 = (struct vmcs12 *)__get_free_page(GFP_KERNEL);
+
+ if (!new_vmcs12 ||
+ kvm_read_guest(vcpu->kvm, vmptr, new_vmcs12,
+ sizeof(*new_vmcs12))) {
+ free_page((unsigned long)new_vmcs12);
+ return nested_vmx_failValid(vcpu,
+ VMXERR_VMPTRLD_INCORRECT_VMCS_REVISION_ID);
+ }

- new_vmcs12 = kmap(page);
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);
+ free_page((unsigned long)new_vmcs12);
return nested_vmx_failValid(vcpu,
- VMXERR_VMPTRLD_INCORRECT_VMCS_REVISION_ID);
+ VMXERR_VMPTRLD_INCORRECT_VMCS_REVISION_ID);
}

nested_release_vmcs12(vcpu);
@@ -9324,9 +9326,7 @@ 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);
-
+ free_page((unsigned long)new_vmcs12);
set_current_vmptr(vmx, vmptr);
}

--
2.7.4
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