KVM: arm64: nv: Extract translation helper from the AT code

The address translation infrastructure is currently pretty tied to
the AT emulation.

However, we also need to features that require the use of VAs, such
as VNCR_EL2 (and maybe one of these days SPE), meaning that we need
a slightly more generic infrastructure.

Start this by introducing a new helper (__kvm_translate_va()) that
performs a S1 walk for a given translation regime, EL and PAN
settings.

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20250514103501.2225951-4-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>

diff --git a/arch/arm64/include/asm/kvm_nested.h b/arch/arm64/include/asm/kvm_nested.h
index 692f403..c8a779b 100644 (file)
--- a/arch/arm64/include/asm/kvm_nested.h
+++ b/arch/arm64/include/asm/kvm_nested.h
@@ -245,4 +245,58 @@ static inline unsigned int ps_to_output_size(unsigned int ps)
        }
 }
 
+enum trans_regime {
+       TR_EL10,
+       TR_EL20,
+       TR_EL2,
+};
+
+struct s1_walk_info {
+       u64                     baddr;
+       enum trans_regime       regime;
+       unsigned int            max_oa_bits;
+       unsigned int            pgshift;
+       unsigned int            txsz;
+       int                     sl;
+       bool                    as_el0;
+       bool                    hpd;
+       bool                    e0poe;
+       bool                    poe;
+       bool                    pan;
+       bool                    be;
+       bool                    s2;
+};
+
+struct s1_walk_result {
+       union {
+               struct {
+                       u64     desc;
+                       u64     pa;
+                       s8      level;
+                       u8      APTable;
+                       bool    UXNTable;
+                       bool    PXNTable;
+                       bool    uwxn;
+                       bool    uov;
+                       bool    ur;
+                       bool    uw;
+                       bool    ux;
+                       bool    pwxn;
+                       bool    pov;
+                       bool    pr;
+                       bool    pw;
+                       bool    px;
+               };
+               struct {
+                       u8      fst;
+                       bool    ptw;
+                       bool    s2;
+               };
+       };
+       bool    failed;
+};
+
+int __kvm_translate_va(struct kvm_vcpu *vcpu, struct s1_walk_info *wi,
+                      struct s1_walk_result *wr, u64 va);
+
 #endif /* __ARM64_KVM_NESTED_H */

diff --git a/arch/arm64/kvm/at.c b/arch/arm64/kvm/at.c
index 7a5267f..7140690 100644 (file)
--- a/arch/arm64/kvm/at.c
+++ b/arch/arm64/kvm/at.c
@@ -10,56 +10,6 @@
 #include <asm/kvm_hyp.h>
 #include <asm/kvm_mmu.h>
 
-enum trans_regime {
-       TR_EL10,
-       TR_EL20,
-       TR_EL2,
-};
-
-struct s1_walk_info {
-       u64                     baddr;
-       enum trans_regime       regime;
-       unsigned int            max_oa_bits;
-       unsigned int            pgshift;
-       unsigned int            txsz;
-       int                     sl;
-       bool                    hpd;
-       bool                    e0poe;
-       bool                    poe;
-       bool                    pan;
-       bool                    be;
-       bool                    s2;
-};
-
-struct s1_walk_result {
-       union {
-               struct {
-                       u64     desc;
-                       u64     pa;
-                       s8      level;
-                       u8      APTable;
-                       bool    UXNTable;
-                       bool    PXNTable;
-                       bool    uwxn;
-                       bool    uov;
-                       bool    ur;
-                       bool    uw;
-                       bool    ux;
-                       bool    pwxn;
-                       bool    pov;
-                       bool    pr;
-                       bool    pw;
-                       bool    px;
-               };
-               struct {
-                       u8      fst;
-                       bool    ptw;
-                       bool    s2;
-               };
-       };
-       bool    failed;
-};
-
 static void fail_s1_walk(struct s1_walk_result *wr, u8 fst, bool s1ptw)
 {
        wr->fst         = fst;
@@ -145,20 +95,15 @@ static void compute_s1poe(struct kvm_vcpu *vcpu, struct s1_walk_info *wi)
        }
 }
 
-static int setup_s1_walk(struct kvm_vcpu *vcpu, u32 op, struct s1_walk_info *wi,
+static int setup_s1_walk(struct kvm_vcpu *vcpu, struct s1_walk_info *wi,
                         struct s1_walk_result *wr, u64 va)
 {
        u64 hcr, sctlr, tcr, tg, ps, ia_bits, ttbr;
        unsigned int stride, x;
-       bool va55, tbi, lva, as_el0;
+       bool va55, tbi, lva;
 
        hcr = __vcpu_sys_reg(vcpu, HCR_EL2);
 
-       wi->regime = compute_translation_regime(vcpu, op);
-       as_el0 = (op == OP_AT_S1E0R || op == OP_AT_S1E0W);
-       wi->pan = (op == OP_AT_S1E1RP || op == OP_AT_S1E1WP) &&
-                 (*vcpu_cpsr(vcpu) & PSR_PAN_BIT);
-
        va55 = va & BIT(55);
 
        if (wi->regime == TR_EL2 && va55)
@@ -319,7 +264,7 @@ static int setup_s1_walk(struct kvm_vcpu *vcpu, u32 op, struct s1_walk_info *wi,
 
        /* R_BNDVG and following statements */
        if (kvm_has_feat(vcpu->kvm, ID_AA64MMFR2_EL1, E0PD, IMP) &&
-           as_el0 && (tcr & (va55 ? TCR_E0PD1 : TCR_E0PD0)))
+           wi->as_el0 && (tcr & (va55 ? TCR_E0PD1 : TCR_E0PD0)))
                goto transfault_l0;
 
        /* AArch64.S1StartLevel() */
@@ -1155,7 +1100,12 @@ static u64 handle_at_slow(struct kvm_vcpu *vcpu, u32 op, u64 vaddr)
        bool perm_fail = false;
        int ret, idx;
 
-       ret = setup_s1_walk(vcpu, op, &wi, &wr, vaddr);
+       wi.regime = compute_translation_regime(vcpu, op);
+       wi.as_el0 = (op == OP_AT_S1E0R || op == OP_AT_S1E0W);
+       wi.pan = (op == OP_AT_S1E1RP || op == OP_AT_S1E1WP) &&
+                (*vcpu_cpsr(vcpu) & PSR_PAN_BIT);
+
+       ret = setup_s1_walk(vcpu, &wi, &wr, vaddr);
        if (ret)
                goto compute_par;
 
@@ -1457,3 +1407,31 @@ void __kvm_at_s12(struct kvm_vcpu *vcpu, u32 op, u64 vaddr)
        par = compute_par_s12(vcpu, par, &out);
        vcpu_write_sys_reg(vcpu, par, PAR_EL1);
 }
+
+/*
+ * Translate a VA for a given EL in a given translation regime, with
+ * or without PAN. This requires wi->{regime, as_el0, pan} to be
+ * set. The rest of the wi and wr should be 0-initialised.
+ */
+int __kvm_translate_va(struct kvm_vcpu *vcpu, struct s1_walk_info *wi,
+                      struct s1_walk_result *wr, u64 va)
+{
+       int ret;
+
+       ret = setup_s1_walk(vcpu, wi, wr, va);
+       if (ret)
+               return ret;
+
+       if (wr->level == S1_MMU_DISABLED) {
+               wr->ur = wr->uw = wr->ux = true;
+               wr->pr = wr->pw = wr->px = true;
+       } else {
+               ret = walk_s1(vcpu, wi, wr, va);
+               if (ret)
+                       return ret;
+
+               compute_s1_permissions(vcpu, wi, wr);
+       }
+
+       return 0;
+}