[PATCH v2 02/12] X86/nVMX: handle_vmptrld: Copy the VMCS12 directly from guest memory

KarimAllah Ahmed
2018-04-15T21:53:08Z

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>
---
v1 -> v2:
- Massage commit message a bit.
---
arch/x86/kvm/vmx.c | 26 +++++++-------------------
1 file changed, 7 insertions(+), 19 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 77fc1ee..810ba7a 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8156,30 +8156,18 @@ static int handle_vmptrld(struct kvm_vcpu *vcpu)
}

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)) {
- nested_vmx_failInvalid(vcpu);
- return kvm_skip_emulated_instruction(vcpu);
- }
- new_vmcs12 = kmap(page);
- if (new_vmcs12->revision_id != VMCS12_REVISION) {
- kunmap(page);
- kvm_release_page_clean(page);
- nested_vmx_failValid(vcpu,
- VMXERR_VMPTRLD_INCORRECT_VMCS_REVISION_ID);
- return kvm_skip_emulated_instruction(vcpu);
- }
-
nested_release_vmcs12(vmx);
+
/*
* Load VMCS12 from guest memory since it is not already
* cached.
*/
- memcpy(vmx->nested.cached_vmcs12, new_vmcs12, VMCS12_SIZE);
- kunmap(page);
- kvm_release_page_clean(page);
+ if (kvm_read_guest(vcpu->kvm, vmptr, vmx->nested.cached_vmcs12,
+ sizeof(*vmx->nested.cached_vmcs12)) ||
+ vmx->nested.cached_vmcs12->revision_id != VMCS12_REVISION) {
+ nested_vmx_failInvalid(vcpu);
+ return kvm_skip_emulated_instruction(vcpu);
+ }

set_current_vmptr(vmx, vmptr);
}
--
2.7.4