[PATCH v2 07/12] KVM/nVMX: Use kvm_vcpu_map when mapping the virtual APIC page

KarimAllah Ahmed
2018-04-15T21:53:13Z

Use kvm_vcpu_map when mapping the virtual APIC page 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
virtual APIC page on the host side.

Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
---
v1 -> v2:
- Do not change the lifecycle of the mapping (pbonzini)
- Use pfn_to_hpa instead of gfn_to_gpa
---
arch/x86/kvm/vmx.c | 34 +++++++++++-----------------------
1 file changed, 11 insertions(+), 23 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 6d335fc..b55053a 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -492,9 +492,8 @@ struct nested_vmx {
* pointers, so we must keep them pinned while L2 runs.
*/
struct page *apic_access_page;
- struct page *virtual_apic_page;
+ struct kvm_host_map virtual_apic_map;
struct page *pi_desc_page;
-
struct kvm_host_map msr_bitmap_map;

struct pi_desc *pi_desc;
@@ -5572,11 +5571,12 @@ static void vmx_complete_nested_posted_interrupt(struct kvm_vcpu *vcpu)

max_irr = find_last_bit((unsigned long *)vmx->nested.pi_desc->pir, 256);
if (max_irr != 256) {
- vapic_page = kmap(vmx->nested.virtual_apic_page);
+ vapic_page = vmx->nested.virtual_apic_map.hva;
+ if (!vapic_page)
+ return;
+
__kvm_apic_update_irr(vmx->nested.pi_desc->pir,
vapic_page, &max_irr);
- kunmap(vmx->nested.virtual_apic_page);
-
status = vmcs_read16(GUEST_INTR_STATUS);
if ((u8)max_irr > ((u8)status & 0xff)) {
status &= ~0xff;
@@ -7806,10 +7806,7 @@ static void free_nested(struct vcpu_vmx *vmx)
kvm_release_page_dirty(vmx->nested.apic_access_page);
vmx->nested.apic_access_page = NULL;
}
- if (vmx->nested.virtual_apic_page) {
- kvm_release_page_dirty(vmx->nested.virtual_apic_page);
- vmx->nested.virtual_apic_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);
@@ -10358,6 +10355,7 @@ static void nested_get_vmcs12_pages(struct kvm_vcpu *vcpu)
{
struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
struct vcpu_vmx *vmx = to_vmx(vcpu);
+ struct kvm_host_map *map;
struct page *page;
u64 hpa;

@@ -10395,11 +10393,7 @@ static void nested_get_vmcs12_pages(struct kvm_vcpu *vcpu)
}

if (nested_cpu_has(vmcs12, CPU_BASED_TPR_SHADOW)) {
- if (vmx->nested.virtual_apic_page) { /* shouldn't happen */
- kvm_release_page_dirty(vmx->nested.virtual_apic_page);
- vmx->nested.virtual_apic_page = NULL;
- }
- page = kvm_vcpu_gpa_to_page(vcpu, vmcs12->virtual_apic_page_addr);
+ map = &vmx->nested.virtual_apic_map;

/*
* If translation failed, VM entry will fail because
@@ -10414,11 +10408,8 @@ static void nested_get_vmcs12_pages(struct kvm_vcpu *vcpu)
* control. But such a configuration is useless, so
* let's keep the code simple.
*/
- if (!is_error_page(page)) {
- vmx->nested.virtual_apic_page = page;
- hpa = page_to_phys(vmx->nested.virtual_apic_page);
- vmcs_write64(VIRTUAL_APIC_PAGE_ADDR, hpa);
- }
+ if (!kvm_vcpu_map(vcpu, gpa_to_gfn(vmcs12->virtual_apic_page_addr), map))
+ vmcs_write64(VIRTUAL_APIC_PAGE_ADDR, pfn_to_hpa(map->pfn));
}

if (nested_cpu_has_posted_intr(vmcs12)) {
@@ -12076,10 +12067,7 @@ 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;
}
- if (vmx->nested.virtual_apic_page) {
- kvm_release_page_dirty(vmx->nested.virtual_apic_page);
- vmx->nested.virtual_apic_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);
--
2.7.4