[PATCH v3 08/13] KVM/nVMX: Use kvm_vcpu_map when mapping the posted interrupt descriptor table

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

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@amazon.de>
---
v1 -> v2:
- Do not change the lifecycle of the mapping (pbonzini)
---
arch/x86/kvm/vmx.c | 45 +++++++++++++++------------------------------
1 file changed, 15 insertions(+), 30 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 83a5e95..0ae25c3 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -846,7 +846,7 @@ 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;

struct pi_desc *pi_desc;
@@ -8469,12 +8469,8 @@ static void free_nested(struct vcpu_vmx *vmx)
vmx->nested.apic_access_page = NULL;
}
kvm_vcpu_unmap(&vmx->nested.virtual_apic_map);
- 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);
+ vmx->nested.pi_desc = NULL;

free_loaded_vmcs(&vmx->nested.vmcs02);
}
@@ -11444,24 +11440,16 @@ 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;
+ 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,
@@ -13344,13 +13332,10 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason,
kvm_release_page_dirty(vmx->nested.apic_access_page);
vmx->nested.apic_access_page = NULL;
}
+
kvm_vcpu_unmap(&vmx->nested.virtual_apic_map);
- 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);
+ vmx->nested.pi_desc = NULL;

/*
* We are now running in L2, mmu_notifier will force to reload the
--
2.7.4