[PATCH 05/15] KVM: arm64: Account for RESx bits in __compute_fgt()

[PATCH 05/15] KVM: arm64: Account for RESx bits in __compute_fgt()

[Marc Zyngier]

When computing Fine Grained Traps, it is preferable to account for
the reserved bits. The HW will most probably ignore them, unless the
bits have been repurposed to do something else.

Use caution, and fold our view of the reserved bits in,

Fixes: c259d763e6b09 ("KVM: arm64: Account for RES1 bits in DECLARE_FEAT_MAP() and co")
Link: https://sashiko.dev/#/patchset/20260319154937.3619520-1-sascha.bischoff%40arm.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
---
 arch/arm64/kvm/config.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/config.c b/arch/arm64/kvm/config.c
index e14685343191b..f35b8dddd7c1f 100644
--- a/arch/arm64/kvm/config.c
+++ b/arch/arm64/kvm/config.c
@@ -1663,8 +1663,8 @@ static __always_inline void __compute_fgt(struct kvm_vcpu *vcpu, enum vcpu_sysre
 		clear |= ~nested & m->nmask;
 	}
 
-	val |= set;
-	val &= ~clear;
+	val |= set | m->res1;
+	val &= ~(clear | m->res0);
 	*vcpu_fgt(vcpu, reg) = val;
 }
 
-- 
2.47.3