[PATCH v2 06/12] KVM/nVMX: Use kvm_vcpu_map when mapping the L1 MSR bitmap

KarimAllah Ahmed
2018-04-15T21:57:11Z

Use kvm_vcpu_map when mapping the L1 MSR bitmap 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>
---
v1 -> v2:
- Do not change the lifecycle of the mapping (pbonzini)
---
arch/x86/kvm/vmx.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 179061d..6d335fc 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -494,6 +494,9 @@ struct nested_vmx {
struct page *apic_access_page;
struct page *virtual_apic_page;
struct page *pi_desc_page;
+
+ struct kvm_host_map msr_bitmap_map;
+
struct pi_desc *pi_desc;
bool pi_pending;
u16 posted_intr_nv;
@@ -10513,9 +10516,10 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu,
struct vmcs12 *vmcs12)
{
int msr;
- struct page *page;
unsigned long *msr_bitmap_l1;
unsigned long *msr_bitmap_l0 = to_vmx(vcpu)->nested.vmcs02.msr_bitmap;
+ struct kvm_host_map *map = &to_vmx(vcpu)->nested.msr_bitmap_map;
+
/*
* pred_cmd & spec_ctrl are trying to verify two things:
*
@@ -10541,11 +10545,10 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu,
!pred_cmd && !spec_ctrl)
return false;

- page = kvm_vcpu_gpa_to_page(vcpu, vmcs12->msr_bitmap);
- if (is_error_page(page))
+ if (kvm_vcpu_map(vcpu, gpa_to_gfn(vmcs12->msr_bitmap), map))
return false;

- msr_bitmap_l1 = (unsigned long *)kmap(page);
+ msr_bitmap_l1 = (unsigned long *)map->hva;
if (nested_cpu_has_apic_reg_virt(vmcs12)) {
/*
* L0 need not intercept reads for MSRs between 0x800 and 0x8ff, it
@@ -10593,8 +10596,7 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu,
MSR_IA32_PRED_CMD,
MSR_TYPE_W);

- kunmap(page);
- kvm_release_page_clean(page);
+ kvm_vcpu_unmap(&to_vmx(vcpu)->nested.msr_bitmap_map);

return true;
}
--
2.7.4