[RESEND PATCH v3 07/13] KVM/nVMX: Use kvm_vcpu_map when mapping the virtual APIC page

KarimAllah Ahmed
2018-10-21T07:39:57Z

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 | 39 +++++++++++++--------------------------
1 file changed, 13 insertions(+), 26 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 5b15ca2..9683923 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -845,9 +845,8 @@ 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;
@@ -6152,11 +6151,12 @@ 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;
@@ -6182,14 +6182,13 @@ static bool vmx_guest_apic_has_interrupt(struct kvm_vcpu *vcpu)

if (WARN_ON_ONCE(!is_guest_mode(vcpu)) ||
!nested_cpu_has_vid(get_vmcs12(vcpu)) ||
- WARN_ON_ONCE(!vmx->nested.virtual_apic_page))
+ WARN_ON_ONCE(!vmx->nested.virtual_apic_map.gfn))
return false;

rvi = vmx_get_rvi();

- vapic_page = kmap(vmx->nested.virtual_apic_page);
+ vapic_page = vmx->nested.virtual_apic_map.hva;
vppr = *((u32 *)(vapic_page + APIC_PROCPRI));
- kunmap(vmx->nested.virtual_apic_page);

return ((rvi & 0xf0) > (vppr & 0xf0));
}
@@ -8468,10 +8467,7 @@ 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);
@@ -11394,6 +11390,7 @@ 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;

@@ -11426,11 +11423,7 @@ 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
@@ -11445,11 +11438,8 @@ 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)) {
@@ -13353,10 +13343,7 @@ 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