Re: [PATCH 06/21] KVM: x86/mmu: Track shadow MMIO value on a per-VM basis

From: Huang, Kai
Date: Mon Mar 11 2024 - 21:22:07 EST




On 28/02/2024 12:20 pm, Paolo Bonzini wrote:
From: Sean Christopherson <seanjc@xxxxxxxxxx>

TDX will use a different shadow PTE entry value for MMIO from VMX. Add > members to kvm_arch and track value for MMIO per-VM instead of global
"members" -> "member".

variables.

"variables" -> "variable".

By using the per-VM EPT entry value for MMIO, the existing VMX
logic is kept working. Introduce a separate setter function so that guest
TD can override later.

"guest TD can override " -> "KVM can override for TDX guest".


Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
Message-Id: <229a18434e5d83f45b1fcd7bf1544d79db1becb6.1705965635.git.isaku.yamahata@xxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 2 ++
arch/x86/kvm/mmu.h | 1 +
arch/x86/kvm/mmu/mmu.c | 8 +++++---
arch/x86/kvm/mmu/spte.c | 10 ++++++++--
arch/x86/kvm/mmu/spte.h | 4 ++--
arch/x86/kvm/mmu/tdp_mmu.c | 6 +++---
6 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 85dc0f7d09e3..a4514c2ef0ec 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1313,6 +1313,8 @@ struct kvm_arch {
*/
spinlock_t mmu_unsync_pages_lock;
+ u64 shadow_mmio_value;
+
struct iommu_domain *iommu_domain;
bool iommu_noncoherent;
#define __KVM_HAVE_ARCH_NONCOHERENT_DMA
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index 60f21bb4c27b..2c54ba5b0a28 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -101,6 +101,7 @@ static inline u8 kvm_get_shadow_phys_bits(void)
}
void kvm_mmu_set_mmio_spte_mask(u64 mmio_value, u64 mmio_mask, u64 access_mask);
+void kvm_mmu_set_mmio_spte_value(struct kvm *kvm, u64 mmio_value);
void kvm_mmu_set_me_spte_mask(u64 me_value, u64 me_mask);
void kvm_mmu_set_ept_masks(bool has_ad_bits, bool has_exec_only);
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index b5baf11359ad..195e46a1f00f 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -2515,7 +2515,7 @@ static int mmu_page_zap_pte(struct kvm *kvm, struct kvm_mmu_page *sp,
return kvm_mmu_prepare_zap_page(kvm, child,
invalid_list);
}
- } else if (is_mmio_spte(pte)) {
+ } else if (is_mmio_spte(kvm, pte)) {
mmu_spte_clear_no_track(spte);
}
return 0;
@@ -4197,7 +4197,7 @@ static int handle_mmio_page_fault(struct kvm_vcpu *vcpu, u64 addr, bool direct)
if (WARN_ON_ONCE(reserved))
return -EINVAL;
- if (is_mmio_spte(spte)) {
+ if (is_mmio_spte(vcpu->kvm, spte)) {
gfn_t gfn = get_mmio_spte_gfn(spte);
unsigned int access = get_mmio_spte_access(spte);
@@ -4813,7 +4813,7 @@ EXPORT_SYMBOL_GPL(kvm_mmu_new_pgd);
static bool sync_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, gfn_t gfn,
unsigned int access)
{
- if (unlikely(is_mmio_spte(*sptep))) {
+ if (unlikely(is_mmio_spte(vcpu->kvm, *sptep))) {
if (gfn != get_mmio_spte_gfn(*sptep)) {
mmu_spte_clear_no_track(sptep);
return true;
@@ -6320,6 +6320,8 @@ static bool kvm_has_zapped_obsolete_pages(struct kvm *kvm)
void kvm_mmu_init_vm(struct kvm *kvm)
{
+
+ kvm->arch.shadow_mmio_value = shadow_mmio_value;

Unintended blank line.

[...]

Acked-by: Kai Huang <kai.huang@xxxxxxxxx>