[PATCH v5 20/37] KVM: arm64: Disable hierarchical permissions when S1PIE is enabled

Marc Zyngier
2024-10-23T14:53:55Z

S1PIE implicitly disables hierarchical permissions, as specified in
R_JHSVW, by making TCR_ELx.HPDn RES1.

Add a predicate for S1PIE being enabled for a given translation regime,
and emulate this behaviour by forcing the hpd field to true if S1PIE
is enabled for that translation regime.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/kvm/at.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)

diff --git a/arch/arm64/kvm/at.c b/arch/arm64/kvm/at.c
index adcfce3f67f03..f5bd750288ff5 100644
--- a/arch/arm64/kvm/at.c
+++ b/arch/arm64/kvm/at.c
@@ -93,6 +93,23 @@ static enum trans_regime compute_translation_regime(struct kvm_vcpu *vcpu, u32 o
}
}

+static bool s1pie_enabled(struct kvm_vcpu *vcpu, enum trans_regime regime)
+{
+ if (!kvm_has_feat(vcpu->kvm, ID_AA64MMFR3_EL1, S1PIE, IMP))
+ return false;
+
+ switch (regime) {
+ case TR_EL2:
+ case TR_EL20:
+ return vcpu_read_sys_reg(vcpu, TCR2_EL2) & TCR2_EL2_PIE;
+ case TR_EL10:
+ return (__vcpu_sys_reg(vcpu, HCRX_EL2) & HCRX_EL2_TCR2En) &&
+ (__vcpu_sys_reg(vcpu, TCR2_EL1) & TCR2_EL1x_PIE);
+ default:
+ BUG();
+ }
+}
+
static int setup_s1_walk(struct kvm_vcpu *vcpu, u32 op, struct s1_walk_info *wi,
struct s1_walk_result *wr, u64 va)
{
@@ -186,6 +203,8 @@ static int setup_s1_walk(struct kvm_vcpu *vcpu, u32 op, struct s1_walk_info *wi,
(va55 ?
FIELD_GET(TCR_HPD1, tcr) :
FIELD_GET(TCR_HPD0, tcr)));
+ /* R_JHSVW */
+ wi->hpd |= s1pie_enabled(vcpu, wi->regime);

/* Someone was silly enough to encode TG0/TG1 differently */
if (va55) {
--
2.39.2