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[v5,09/30] KVM: arm64: use `at s1e1a` for POE

Message ID 20240822151113.1479789-10-joey.gouly@arm.com (mailing list archive)
State Accepted
Commit 55f4b215fb60f81e97d716fae42f967e435ce156
Headers show
Series Permission Overlay Extension | expand

Commit Message

Joey Gouly Aug. 22, 2024, 3:10 p.m. UTC 
FEAT_ATS1E1A introduces a new instruction: `at s1e1a`.
This is an address translation, without permission checks.

POE allows read permissions to be removed from S1 by the guest.  This means
that an `at` instruction could fail, and not get the IPA.

Switch to using `at s1e1a` so that KVM can get the IPA regardless of S1
permissions.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/hyp/include/hyp/fault.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
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Patch

diff --git arch/arm64/kvm/hyp/include/hyp/fault.h arch/arm64/kvm/hyp/include/hyp/fault.h
index 487c06099d6f..17df94570f03 100644
--- arch/arm64/kvm/hyp/include/hyp/fault.h
+++ arch/arm64/kvm/hyp/include/hyp/fault.h
@@ -14,6 +14,7 @@ 
 
 static inline bool __translate_far_to_hpfar(u64 far, u64 *hpfar)
 {
+	int ret;
 	u64 par, tmp;
 
 	/*
@@ -27,7 +28,9 @@  static inline bool __translate_far_to_hpfar(u64 far, u64 *hpfar)
 	 * saved the guest context yet, and we may return early...
 	 */
 	par = read_sysreg_par();
-	if (!__kvm_at(OP_AT_S1E1R, far))
+	ret = system_supports_poe() ? __kvm_at(OP_AT_S1E1A, far) :
+	                              __kvm_at(OP_AT_S1E1R, far);
+	if (!ret)
 		tmp = read_sysreg_par();
 	else
 		tmp = SYS_PAR_EL1_F; /* back to the guest */