[PATCH v3 10/18] KVM: arm64: nv: Add basic emulation of AT S1E1{R,W}P

Marc Zyngier
2024-08-13T10:06:23Z

Building on top of our primitive AT S1E{0,1}{R,W} emulation,
add minimal support for the FEAT_PAN2 instructions, momentary
context-switching PSTATE.PAN so that it takes effect in the
context of the guest.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/kvm/at.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)

diff --git a/arch/arm64/kvm/at.c b/arch/arm64/kvm/at.c
index da378ad834cd..92df948350e1 100644
--- a/arch/arm64/kvm/at.c
+++ b/arch/arm64/kvm/at.c
@@ -49,6 +49,28 @@ static void __mmu_config_restore(struct mmu_config *config)
write_sysreg(config->vtcr, vtcr_el2);
}

+static bool at_s1e1p_fast(struct kvm_vcpu *vcpu, u32 op, u64 vaddr)
+{
+ u64 host_pan;
+ bool fail;
+
+ host_pan = read_sysreg_s(SYS_PSTATE_PAN);
+ write_sysreg_s(*vcpu_cpsr(vcpu) & PSTATE_PAN, SYS_PSTATE_PAN);
+
+ switch (op) {
+ case OP_AT_S1E1RP:
+ fail = __kvm_at(OP_AT_S1E1RP, vaddr);
+ break;
+ case OP_AT_S1E1WP:
+ fail = __kvm_at(OP_AT_S1E1WP, vaddr);
+ break;
+ }
+
+ write_sysreg_s(host_pan, SYS_PSTATE_PAN);
+
+ return fail;
+}
+
/*
* Return the PAR_EL1 value as the result of a valid translation.
*
@@ -105,6 +127,10 @@ static u64 __kvm_at_s1e01_fast(struct kvm_vcpu *vcpu, u32 op, u64 vaddr)
isb();

switch (op) {
+ case OP_AT_S1E1RP:
+ case OP_AT_S1E1WP:
+ fail = at_s1e1p_fast(vcpu, op, vaddr);
+ break;
case OP_AT_S1E1R:
fail = __kvm_at(OP_AT_S1E1R, vaddr);
break;
--
2.39.2