KVM: x86/mmu: Plumb param "old_spte" into kvm_x86_ops.set_external_spte()

If tdp_mmu_set_spte_atomic() triggers an atomic zap on a mirror SPTE
(though currently no paths trigger it), the change is propagated via the
set_external_spte() op. Plumb the old SPTE into the set_external_spte() op,
so TDX code rather than TDP MMU code can warn if the atomic zap isn't
allowed, i.e. to let TDX enforce TDX's rules (inasmuch as possible).

Rename mirror_spte to new_spte to follow the TDP MMU's naming, and to make
it more obvious what value the parameter holds.

Opportunistically tweak the ordering of parameters to match the pattern of
most TDP MMU functions, which do "old, new, level".

Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Link: https://patch.msgid.link/20260509075533.4193-1-yan.y.zhao@intel.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 85339d43a9ff6c59a54988a1d1067d0b318cda9f..b8ca43241b11545569a5152e49efbb2136ceadde 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1912,8 +1912,8 @@ struct kvm_x86_ops {
                             int root_level);
 
        /* Update the external page table from spte getting set. */
-       int (*set_external_spte)(struct kvm *kvm, gfn_t gfn, enum pg_level level,
-                                u64 mirror_spte);
+       int (*set_external_spte)(struct kvm *kvm, gfn_t gfn, u64 old_spte,
+                                u64 new_spte, enum pg_level level);
 
        /* Update external page tables for page table about to be freed. */
        int (*free_external_spt)(struct kvm *kvm, gfn_t gfn, enum pg_level level,

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 128089571e34caab51ac6b24148b7e102ad17b75..4e961b331780ba1f26599dc55fd077e46e6d9256 100644 (file)
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -632,8 +632,8 @@ static inline int __must_check __tdp_mmu_set_spte_atomic(struct kvm *kvm,
                if (!try_cmpxchg64(raw_sptep, &iter->old_spte, FROZEN_SPTE))
                        return -EBUSY;
 
-               ret = kvm_x86_call(set_external_spte)(kvm, iter->gfn, iter->level,
-                                                     new_spte);
+               ret = kvm_x86_call(set_external_spte)(kvm, iter->gfn, iter->old_spte,
+                                                     new_spte, iter->level);
 
                if (ret)
                        __kvm_tdp_mmu_write_spte(iter->sptep, iter->old_spte);

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 965c1244e733dcd7ebe6ecd6b4936cd79b5139b4..c7ca5c79ada2044e744b7de4319d64c2ca1a10d7 100644 (file)
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -1667,13 +1667,13 @@ static struct page *tdx_spte_to_sept_pt(struct kvm *kvm, gfn_t gfn,
 }
 
 static int tdx_sept_map_nonleaf_spte(struct kvm *kvm, gfn_t gfn,
-                                    enum pg_level level, u64 mirror_spte)
+                                    enum pg_level level, u64 new_spte)
 {
        gpa_t gpa = gfn_to_gpa(gfn);
        u64 err, entry, level_state;
        struct page *sept_pt;
 
-       sept_pt = tdx_spte_to_sept_pt(kvm, gfn, mirror_spte, level);
+       sept_pt = tdx_spte_to_sept_pt(kvm, gfn, new_spte, level);
        if (!sept_pt)
                return -EIO;
 
@@ -1689,16 +1689,16 @@ static int tdx_sept_map_nonleaf_spte(struct kvm *kvm, gfn_t gfn,
 }
 
 static int tdx_sept_map_leaf_spte(struct kvm *kvm, gfn_t gfn, enum pg_level level,
-                                 u64 mirror_spte)
+                                 u64 new_spte)
 {
        struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
-       kvm_pfn_t pfn = spte_to_pfn(mirror_spte);
+       kvm_pfn_t pfn = spte_to_pfn(new_spte);
 
        /* TODO: handle large pages. */
        if (KVM_BUG_ON(level != PG_LEVEL_4K, kvm))
                return -EIO;
 
-       WARN_ON_ONCE((mirror_spte & VMX_EPT_RWX_MASK) != VMX_EPT_RWX_MASK);
+       WARN_ON_ONCE((new_spte & VMX_EPT_RWX_MASK) != VMX_EPT_RWX_MASK);
 
        /*
         * Ensure pre_fault_allowed is read by kvm_arch_vcpu_pre_fault_memory()
@@ -1718,16 +1718,16 @@ static int tdx_sept_map_leaf_spte(struct kvm *kvm, gfn_t gfn, enum pg_level leve
        return tdx_mem_page_aug(kvm, gfn, level, pfn);
 }
 
-static int tdx_sept_set_private_spte(struct kvm *kvm, gfn_t gfn,
-                                    enum pg_level level, u64 mirror_spte)
+static int tdx_sept_set_private_spte(struct kvm *kvm, gfn_t gfn, u64 old_spte,
+                                    u64 new_spte, enum pg_level level)
 {
-       if (KVM_BUG_ON(!is_shadow_present_pte(mirror_spte), kvm))
+       if (KVM_BUG_ON(!is_shadow_present_pte(new_spte), kvm))
                return -EIO;
 
-       if (!is_last_spte(mirror_spte, level))
-               return tdx_sept_map_nonleaf_spte(kvm, gfn, level, mirror_spte);
+       if (!is_last_spte(new_spte, level))
+               return tdx_sept_map_nonleaf_spte(kvm, gfn, level, new_spte);
 
-       return tdx_sept_map_leaf_spte(kvm, gfn, level, mirror_spte);
+       return tdx_sept_map_leaf_spte(kvm, gfn, level, new_spte);
 }
 
 /*