[PATCH v3 13/13] KVM/nVMX: Use kvm_vcpu_map for accessing the shadow VMCS

KarimAllah Ahmed
2018-10-20T22:22:25Z

Use kvm_vcpu_map for accessing the shadow VMCS since using
kvm_vcpu_gpa_to_page() and kmap() will only work for guest memory that has
a "struct page".

Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
---
arch/x86/kvm/vmx.c | 25 ++++++++++++-------------
1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 0ae25c3..2892770 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -11616,20 +11616,20 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu,
static void nested_cache_shadow_vmcs12(struct kvm_vcpu *vcpu,
struct vmcs12 *vmcs12)
{
+ struct kvm_host_map map;
struct vmcs12 *shadow;
- struct page *page;

if (!nested_cpu_has_shadow_vmcs(vmcs12) ||
vmcs12->vmcs_link_pointer == -1ull)
return;

shadow = get_shadow_vmcs12(vcpu);
- page = kvm_vcpu_gpa_to_page(vcpu, vmcs12->vmcs_link_pointer);

- memcpy(shadow, kmap(page), VMCS12_SIZE);
+ if (kvm_vcpu_map(vcpu, gpa_to_gfn(vmcs12->vmcs_link_pointer), &map))
+ return;

- kunmap(page);
- kvm_release_page_clean(page);
+ memcpy(shadow, map.hva, VMCS12_SIZE);
+ kvm_vcpu_unmap(&map);
}

static void nested_flush_cached_shadow_vmcs12(struct kvm_vcpu *vcpu,
@@ -12494,9 +12494,9 @@ static int check_vmentry_prereqs(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
static int nested_vmx_check_vmcs_link_ptr(struct kvm_vcpu *vcpu,
struct vmcs12 *vmcs12)
{
- int r;
- struct page *page;
+ int r = 0;
struct vmcs12 *shadow;
+ struct kvm_host_map map;

if (vmcs12->vmcs_link_pointer == -1ull)
return 0;
@@ -12504,17 +12504,16 @@ static int nested_vmx_check_vmcs_link_ptr(struct kvm_vcpu *vcpu,
if (!page_address_valid(vcpu, vmcs12->vmcs_link_pointer))
return -EINVAL;

- page = kvm_vcpu_gpa_to_page(vcpu, vmcs12->vmcs_link_pointer);
- if (is_error_page(page))
+ if (kvm_vcpu_map(vcpu, gpa_to_gfn(vmcs12->vmcs_link_pointer), &map))
return -EINVAL;

- r = 0;
- shadow = kmap(page);
+ shadow = map.hva;
+
if (shadow->hdr.revision_id != VMCS12_REVISION ||
shadow->hdr.shadow_vmcs != nested_cpu_has_shadow_vmcs(vmcs12))
r = -EINVAL;
- kunmap(page);
- kvm_release_page_clean(page);
+
+ kvm_vcpu_unmap(&map);
return r;
}

--
2.7.4