diff options
| author | Oliver Upton <oupton@kernel.org> | 2026-01-08 23:42:30 +0300 |
|---|---|---|
| committer | Oliver Upton <oupton@kernel.org> | 2026-01-10 02:40:34 +0300 |
| commit | 9e27085c33cca7ad26bec0af2c17aab072dd802e (patch) | |
| tree | abdc0ae6f0459cb4f2fe0733d58cac1b740f118e | |
| parent | 9cb2c20f06c300f92a831e4c374e353b33c5582b (diff) | |
| download | linux-9e27085c33cca7ad26bec0af2c17aab072dd802e.tar.xz | |
KVM: arm64: nv: Respect stage-2 write permssion when setting stage-1 AF
Naturally, updating the Access Flag in a stage-1 descriptor requires
write permission at stage-2, although this isn't actually enforced in
KVM's software PTW.
Generate a stage-2 permission fault if the stage-1 walk attempts to
update the descriptor and its corresponding stage-2 translation lacks
write permission.
Fixes: bff8aa213dee ("KVM: arm64: Implement HW access flag management in stage-1 SW PTW")
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://msgid.link/20260108204230.677172-1-oupton@kernel.org
Signed-off-by: Oliver Upton <oupton@kernel.org>
| -rw-r--r-- | arch/arm64/kvm/at.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/arch/arm64/kvm/at.c b/arch/arm64/kvm/at.c index 53bf70126f81..808d26bed182 100644 --- a/arch/arm64/kvm/at.c +++ b/arch/arm64/kvm/at.c @@ -403,6 +403,7 @@ static int walk_s1(struct kvm_vcpu *vcpu, struct s1_walk_info *wi, struct s1_walk_result *wr, u64 va) { u64 va_top, va_bottom, baddr, desc, new_desc, ipa; + struct kvm_s2_trans s2_trans = {}; int level, stride, ret; level = wi->sl; @@ -420,8 +421,6 @@ static int walk_s1(struct kvm_vcpu *vcpu, struct s1_walk_info *wi, ipa = baddr | index; if (wi->s2) { - struct kvm_s2_trans s2_trans = {}; - ret = kvm_walk_nested_s2(vcpu, ipa, &s2_trans); if (ret) { fail_s1_walk(wr, @@ -515,6 +514,11 @@ static int walk_s1(struct kvm_vcpu *vcpu, struct s1_walk_info *wi, new_desc |= PTE_AF; if (new_desc != desc) { + if (wi->s2 && !kvm_s2_trans_writable(&s2_trans)) { + fail_s1_walk(wr, ESR_ELx_FSC_PERM_L(level), true); + return -EPERM; + } + ret = kvm_swap_s1_desc(vcpu, ipa, desc, new_desc, wi); if (ret) return ret; |