Commit 949019b9 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: x86/mmu: Track shadow MMIO value on a per-VM basis 



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

Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarIsaku Yamahata <isaku.yamahata@intel.com>
Message-Id: <229a18434e5d83f45b1fcd7bf1544d79db1becb6.1705965635.git.isaku.yamahata@intel.com>
Reviewed-by: default avatarXiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: default avatarBinbin Wu <binbin.wu@linux.intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 7fa5e292

arch/x86/include/asm/kvm_host.h

+2 −0
Original line number Diff line number Diff line
@@ -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

arch/x86/kvm/mmu/mmu.c

+4 −3
Original line number Diff line number Diff line
@@ -2462,7 +2462,7 @@ 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;
@@ -4144,7 +4144,7 @@ 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);
@@ -4760,7 +4760,7 @@ 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;
@@ -6267,6 +6267,7 @@ 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;

	INIT_LIST_HEAD(&kvm->arch.active_mmu_pages);

	INIT_LIST_HEAD(&kvm->arch.zapped_obsolete_pages);

	INIT_LIST_HEAD(&kvm->arch.possible_nx_huge_pages);

arch/x86/kvm/mmu/spte.c

+2 −2
Original line number Diff line number Diff line
@@ -74,10 +74,10 @@ u64 make_mmio_spte(struct kvm_vcpu *vcpu, u64 gfn, unsigned int access) 
	u64 spte = generation_mmio_spte_mask(gen);

	u64 gpa = gfn << PAGE_SHIFT;



	WARN_ON_ONCE(!shadow_mmio_value);

	WARN_ON_ONCE(!vcpu->kvm->arch.shadow_mmio_value);



	access &= shadow_mmio_access_mask;

	spte |= shadow_mmio_value | access;

	spte |= vcpu->kvm->arch.shadow_mmio_value | access;

	spte |= gpa | shadow_nonpresent_or_rsvd_mask;

	spte |= (gpa & shadow_nonpresent_or_rsvd_mask)

		<< SHADOW_NONPRESENT_OR_RSVD_MASK_LEN;

arch/x86/kvm/mmu/spte.h

+2 −2
Original line number Diff line number Diff line
@@ -265,9 +265,9 @@ static inline struct kvm_mmu_page *root_to_sp(hpa_t root) 
	return spte_to_child_sp(root);

}



static inline bool is_mmio_spte(u64 spte)

static inline bool is_mmio_spte(struct kvm *kvm, u64 spte)

{

	return (spte & shadow_mmio_mask) == shadow_mmio_value &&

	return (spte & shadow_mmio_mask) == kvm->arch.shadow_mmio_value &&

	       likely(enable_mmio_caching);

}

arch/x86/kvm/mmu/tdp_mmu.c

+3 −3
Original line number Diff line number Diff line
@@ -495,8 +495,8 @@ static void handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn, 
		 * impact the guest since both the former and current SPTEs

		 * are nonpresent.

		 */

		if (WARN_ON_ONCE(!is_mmio_spte(old_spte) &&

				 !is_mmio_spte(new_spte) &&

		if (WARN_ON_ONCE(!is_mmio_spte(kvm, old_spte) &&

				 !is_mmio_spte(kvm, new_spte) &&

				 !is_removed_spte(new_spte)))

			pr_err("Unexpected SPTE change! Nonpresent SPTEs\n"

			       "should not be replaced with another,\n"
@@ -1028,7 +1028,7 @@ static int tdp_mmu_map_handle_target_level(struct kvm_vcpu *vcpu, 
	}



	/* If a MMIO SPTE is installed, the MMIO will need to be emulated. */

	if (unlikely(is_mmio_spte(new_spte))) {

	if (unlikely(is_mmio_spte(vcpu->kvm, new_spte))) {

		vcpu->stat.pf_mmio_spte_created++;

		trace_mark_mmio_spte(rcu_dereference(iter->sptep), iter->gfn,

				     new_spte);