KVM: arm64: Compute shareability for LPA2

LPA2 gets the memory access shareability from TCR_ELx instead of
getting it form the descriptors. Store it in the walk info struct
so that it is passed around and evaluated as required.

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
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 1a03095b03c5b82876758f3d3a7dfc0ab95770b8..f3135ded47b7d8dca2d7795e95af532ab890ce90 100644 (file)
--- a/arch/arm64/include/asm/kvm_nested.h
+++ b/arch/arm64/include/asm/kvm_nested.h
@@ -295,6 +295,7 @@ struct s1_walk_info {
        unsigned int            pgshift;
        unsigned int            txsz;
        int                     sl;
+       u8                      sh;
        bool                    as_el0;
        bool                    hpd;
        bool                    e0poe;

diff --git a/arch/arm64/kvm/at.c b/arch/arm64/kvm/at.c
index acf6a5d4977731fc5ef4c67d95067046173faac6..410d12b5b0ac3b3bd5e671b1e9c449f6dd28e69e 100644 (file)
--- a/arch/arm64/kvm/at.c
+++ b/arch/arm64/kvm/at.c
@@ -188,6 +188,12 @@ static int setup_s1_walk(struct kvm_vcpu *vcpu, struct s1_walk_info *wi,
        if (!tbi && (u64)sign_extend64(va, 55) != va)
                goto addrsz;
 
+       wi->sh = (wi->regime == TR_EL2 ?
+                 FIELD_GET(TCR_EL2_SH0_MASK, tcr) :
+                 (va55 ?
+                  FIELD_GET(TCR_SH1_MASK, tcr) :
+                  FIELD_GET(TCR_SH0_MASK, tcr)));
+
        va = (u64)sign_extend64(va, 55);
 
        /* Let's put the MMU disabled case aside immediately */
@@ -697,21 +703,36 @@ static u8 combine_s1_s2_attr(u8 s1, u8 s2)
 #define ATTR_OSH       0b10
 #define ATTR_ISH       0b11
 
-static u8 compute_sh(u8 attr, u64 desc)
+static u8 compute_final_sh(u8 attr, u8 sh)
 {
-       u8 sh;
-
        /* Any form of device, as well as NC has SH[1:0]=0b10 */
        if (MEMATTR_IS_DEVICE(attr) || attr == MEMATTR(NC, NC))
                return ATTR_OSH;
 
-       sh = FIELD_GET(PTE_SHARED, desc);
        if (sh == ATTR_RSV)             /* Reserved, mapped to NSH */
                sh = ATTR_NSH;
 
        return sh;
 }
 
+static u8 compute_s1_sh(struct s1_walk_info *wi, struct s1_walk_result *wr,
+                       u8 attr)
+{
+       u8 sh;
+
+       /*
+        * non-52bit and LPA have their basic shareability described in the
+        * descriptor. LPA2 gets it from the corresponding field in TCR,
+        * conveniently recorded in the walk info.
+        */
+       if (!wi->pa52bit || BIT(wi->pgshift) == SZ_64K)
+               sh = FIELD_GET(KVM_PTE_LEAF_ATTR_LO_S1_SH, wr->desc);
+       else
+               sh = wi->sh;
+
+       return compute_final_sh(attr, sh);
+}
+
 static u8 combine_sh(u8 s1_sh, u8 s2_sh)
 {
        if (s1_sh == ATTR_OSH || s2_sh == ATTR_OSH)
@@ -725,7 +746,7 @@ static u8 combine_sh(u8 s1_sh, u8 s2_sh)
 static u64 compute_par_s12(struct kvm_vcpu *vcpu, u64 s1_par,
                           struct kvm_s2_trans *tr)
 {
-       u8 s1_parattr, s2_memattr, final_attr;
+       u8 s1_parattr, s2_memattr, final_attr, s2_sh;
        u64 par;
 
        /* If S2 has failed to translate, report the damage */
@@ -798,11 +819,13 @@ static u64 compute_par_s12(struct kvm_vcpu *vcpu, u64 s1_par,
            !MEMATTR_IS_DEVICE(final_attr))
                final_attr = MEMATTR(NC, NC);
 
+       s2_sh = FIELD_GET(KVM_PTE_LEAF_ATTR_LO_S2_SH, tr->desc);
+
        par  = FIELD_PREP(SYS_PAR_EL1_ATTR, final_attr);
        par |= tr->output & GENMASK(47, 12);
        par |= FIELD_PREP(SYS_PAR_EL1_SH,
                          combine_sh(FIELD_GET(SYS_PAR_EL1_SH, s1_par),
-                                    compute_sh(final_attr, tr->desc)));
+                                    compute_final_sh(final_attr, s2_sh)));
 
        return par;
 }
@@ -856,7 +879,7 @@ static u64 compute_par_s1(struct kvm_vcpu *vcpu, struct s1_walk_info *wi,
                par |= FIELD_PREP(SYS_PAR_EL1_ATTR, mair);
                par |= wr->pa & GENMASK_ULL(47, 12);
 
-               sh = compute_sh(mair, wr->desc);
+               sh = compute_s1_sh(wi, wr, mair);
                par |= FIELD_PREP(SYS_PAR_EL1_SH, sh);
        }