For nested guests the pi_desc_page 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 <pbonz...@redhat.com>
Cc: Radim Krčmář <rkrc...@redhat.com>
Cc: k...@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: KarimAllah Ahmed <karah...@amazon.de>
---
 arch/x86/kvm/vmx.c | 40 ++++++++++++++++++----------------------
 1 file changed, 18 insertions(+), 22 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 6bd0c45..40d73f4 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -453,7 +453,7 @@ struct nested_vmx {
         */
        struct kvm_host_mapping apic_access_mapping;
        struct kvm_host_mapping virtual_apic_mapping;
-       struct page *pi_desc_page;
+       struct kvm_host_mapping pi_desc_mapping;
        struct pi_desc *pi_desc;
        bool pi_pending;
        u16 posted_intr_nv;
@@ -7501,12 +7501,11 @@ static void free_nested(struct vcpu_vmx *vmx)
        /* Unpin physical memory we referred to in the vmcs02 */
        if (vmx->nested.apic_access_mapping.pfn)
                kvm_release_host_mapping(&vmx->nested.apic_access_mapping, 
true);
+
        if (vmx->nested.virtual_apic_mapping.pfn)
                kvm_release_host_mapping(&vmx->nested.virtual_apic_mapping, 
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;
+       if (vmx->nested.pi_desc_mapping.pfn) {
+               kvm_release_host_mapping(&vmx->nested.pi_desc_mapping, true);
                vmx->nested.pi_desc = NULL;
        }
 
@@ -10041,7 +10040,6 @@ static void nested_get_vmcs12_pages(struct kvm_vcpu 
*vcpu,
                                        struct vmcs12 *vmcs12)
 {
        struct vcpu_vmx *vmx = to_vmx(vcpu);
-       struct page *page;
 
        if (nested_cpu_has2(vmcs12, SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES)) {
                /*
@@ -10097,24 +10095,22 @@ 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;
-               }
-               page = kvm_vcpu_gpa_to_page(vcpu, 
vmcs12->posted_intr_desc_addr);
-               if (is_error_page(page))
+               if (vmx->nested.pi_desc_mapping.pfn) /* shouldn't happen */
+                       kvm_release_host_mapping(&vmx->nested.pi_desc_mapping, 
true);
+
+               if (!kvm_vcpu_gpa_to_host_mapping(vcpu, 
vmcs12->posted_intr_desc_addr,
+                                                 &vmx->nested.pi_desc_mapping, 
true))
                        return;
-               vmx->nested.pi_desc_page = page;
-               vmx->nested.pi_desc = kmap(vmx->nested.pi_desc_page);
+
+               vmx->nested.pi_desc = vmx->nested.pi_desc_mapping.kaddr;
                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)));
+                            (vmx->nested.pi_desc_mapping.pfn << PAGE_SHIFT) +
+                            (unsigned long)(vmcs12->posted_intr_desc_addr &
+                                            (PAGE_SIZE - 1)));
        }
        if (cpu_has_vmx_msr_bitmap() &&
            nested_cpu_has(vmcs12, CPU_BASED_USE_MSR_BITMAPS) &&
@@ -11675,12 +11671,12 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, 
u32 exit_reason,
        /* Unpin physical memory we referred to in vmcs02 */
        if (vmx->nested.apic_access_mapping.pfn)
                kvm_release_host_mapping(&vmx->nested.apic_access_mapping, 
true);
+
        if (vmx->nested.virtual_apic_mapping.pfn)
                kvm_release_host_mapping(&vmx->nested.virtual_apic_mapping, 
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;
+
+       if (vmx->nested.pi_desc_mapping.pfn) {
+               kvm_release_host_mapping(&vmx->nested.pi_desc_mapping, true);
                vmx->nested.pi_desc = NULL;
        }
 
-- 
2.7.4

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