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Subject[RFC 05/12] KVM/VMX: Use the new host mapping API for mapping nested vmptr
Date
For nested guests the vmptr was mapped to the host kernel using
kvm_vcpu_gpa_to_page which assumes that all guest memory is backed by a
"struct page". This breaks guests that have their memory outside the kernel
control.

Switch to the new host mapping API which takes care of this use-case as
well.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
---
arch/x86/kvm/vmx.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 40d73f4..9e45bd1 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -7364,7 +7364,7 @@ static int handle_vmon(struct kvm_vcpu *vcpu)
{
int ret;
gpa_t vmptr;
- struct page *page;
+ struct kvm_host_mapping mapping;
struct vcpu_vmx *vmx = to_vmx(vcpu);
const u64 VMXON_NEEDED_FEATURES = FEATURE_CONTROL_LOCKED
| FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX;
@@ -7410,19 +7410,17 @@ static int handle_vmon(struct kvm_vcpu *vcpu)
return kvm_skip_emulated_instruction(vcpu);
}

- page = kvm_vcpu_gpa_to_page(vcpu, vmptr);
- if (is_error_page(page)) {
+ if (!kvm_vcpu_gpa_to_host_mapping(vcpu, vmptr, &mapping, true)) {
nested_vmx_failInvalid(vcpu);
return kvm_skip_emulated_instruction(vcpu);
}
- if (*(u32 *)kmap(page) != VMCS12_REVISION) {
- kunmap(page);
- kvm_release_page_clean(page);
+ if (*(u32 *)mapping.kaddr != VMCS12_REVISION) {
+ kvm_release_host_mapping(&mapping, false);
nested_vmx_failInvalid(vcpu);
return kvm_skip_emulated_instruction(vcpu);
}
- kunmap(page);
- kvm_release_page_clean(page);
+
+ kvm_release_host_mapping(&mapping, false);

vmx->nested.vmxon_ptr = vmptr;
ret = enter_vmx_operation(vcpu);
--
2.7.4
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