[PATCH v4 06/14] KVM/nVMX: Use kvm_vcpu_map when mapping the L1 MSR bitmap

[KarimAllah Ahmed]

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@xxxxxxxxx>
---
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 6d6dfa9..cca3ba0 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -867,6 +867,9 @@ 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;
@@ -12069,9 +12072,10 @@ 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:
 	 *
@@ -12097,11 +12101,10 @@ 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
@@ -12149,8 +12152,7 @@ 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