[PATCH v5 08/13] KVM/nVMX: Use kvm_vcpu_map when mapping the posted interrupt descriptor table

[KarimAllah Ahmed]

Use kvm_vcpu_map when mapping the posted interrupt descriptor table since
using kvm_vcpu_gpa_to_page() and kmap() will only work for guest memory
that has a "struct page".

One additional semantic change is that the virtual host mapping lifecycle
has changed a bit. It now has the same lifetime of the pinning of the
interrupt descriptor table page on the host side.

Signed-off-by: KarimAllah Ahmed <karahmed@xxxxxxxxx>
---
v4 -> v5:
- unmap with dirty flag

v1 -> v2:
- Do not change the lifecycle of the mapping (pbonzini)
---
 arch/x86/kvm/vmx/nested.c | 43 ++++++++++++-------------------------------
 arch/x86/kvm/vmx/vmx.h    |  2 +-
 2 files changed, 13 insertions(+), 32 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index dcff99d..b4230ce 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -230,12 +230,8 @@ static void free_nested(struct kvm_vcpu *vcpu)
 		vmx->nested.apic_access_page = NULL;
 	}
 	kvm_vcpu_unmap(&vmx->nested.virtual_apic_map, true);
-	if (vmx->nested.pi_desc_page) {
-		kunmap(vmx->nested.pi_desc_page);
-		kvm_release_page_dirty(vmx->nested.pi_desc_page);
-		vmx->nested.pi_desc_page = NULL;
-		vmx->nested.pi_desc = NULL;
-	}
+	kvm_vcpu_unmap(&vmx->nested.pi_desc_map, true);
+	vmx->nested.pi_desc = NULL;
 
 	kvm_mmu_free_roots(vcpu, &vcpu->arch.guest_mmu, KVM_MMU_ROOTS_ALL);
 
@@ -2868,26 +2864,15 @@ static void nested_get_vmcs12_pages(struct kvm_vcpu *vcpu)
 	}
 
 	if (nested_cpu_has_posted_intr(vmcs12)) {
-		if (vmx->nested.pi_desc_page) { /* shouldn't happen */
-			kunmap(vmx->nested.pi_desc_page);
-			kvm_release_page_dirty(vmx->nested.pi_desc_page);
-			vmx->nested.pi_desc_page = NULL;
-			vmx->nested.pi_desc = NULL;
-			vmcs_write64(POSTED_INTR_DESC_ADDR, -1ull);
+		map = &vmx->nested.pi_desc_map;
+
+		if (!kvm_vcpu_map(vcpu, gpa_to_gfn(vmcs12->posted_intr_desc_addr), map)) {
+			vmx->nested.pi_desc =
+				(struct pi_desc *)(((void *)map->hva) +
+				offset_in_page(vmcs12->posted_intr_desc_addr));
+			vmcs_write64(POSTED_INTR_DESC_ADDR,
+				     pfn_to_hpa(map->pfn) + offset_in_page(vmcs12->posted_intr_desc_addr));
 		}
-		page = kvm_vcpu_gpa_to_page(vcpu, vmcs12->posted_intr_desc_addr);
-		if (is_error_page(page))
-			return;
-		vmx->nested.pi_desc_page = page;
-		vmx->nested.pi_desc = kmap(vmx->nested.pi_desc_page);
-		vmx->nested.pi_desc =
-			(struct pi_desc *)((void *)vmx->nested.pi_desc +
-			(unsigned long)(vmcs12->posted_intr_desc_addr &
-			(PAGE_SIZE - 1)));
-		vmcs_write64(POSTED_INTR_DESC_ADDR,
-			page_to_phys(vmx->nested.pi_desc_page) +
-			(unsigned long)(vmcs12->posted_intr_desc_addr &
-			(PAGE_SIZE - 1)));
 	}
 	if (nested_vmx_prepare_msr_bitmap(vcpu, vmcs12))
 		vmcs_set_bits(CPU_BASED_VM_EXEC_CONTROL,
@@ -3911,12 +3896,8 @@ void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason,
 		vmx->nested.apic_access_page = NULL;
 	}
 	kvm_vcpu_unmap(&vmx->nested.virtual_apic_map, true);
-	if (vmx->nested.pi_desc_page) {
-		kunmap(vmx->nested.pi_desc_page);
-		kvm_release_page_dirty(vmx->nested.pi_desc_page);
-		vmx->nested.pi_desc_page = NULL;
-		vmx->nested.pi_desc = NULL;
-	}
+	kvm_vcpu_unmap(&vmx->nested.pi_desc_map, true);
+	vmx->nested.pi_desc = NULL;
 
 	/*
 	 * We are now running in L2, mmu_notifier will force to reload the
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index f618f52..bd04725 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -143,7 +143,7 @@ struct nested_vmx {
 	 */
 	struct page *apic_access_page;
 	struct kvm_host_map virtual_apic_map;
-	struct page *pi_desc_page;
+	struct kvm_host_map pi_desc_map;
 
 	struct kvm_host_map msr_bitmap_map;
 
-- 
2.7.4