[PATCH v6 08/14] KVM/nVMX: Use kvm_vcpu_map when mapping the posted interrupt descriptor table

From: KarimAllah Ahmed
Date: Thu Jan 31 2019 - 15:28:17 EST


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>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
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 31b352c..53b1063 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(vcpu, &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(vcpu, &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(vcpu, &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(vcpu, &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