[PATCH 5/5] KVM: arm64: nv: Restart stage-1 walk if stage-2 desc update fails

[Oliver Upton <oupton@kernel.org>]

kvm_walk_nested_s2() returns -EAGAIN as an indication that an underlying
descriptor update fails due to a race. The expectation is that the
caller restart translation, yet walk_s1() actually synthesizes an abort.

Propagate the -EAGAIN return out of walk_s1(), relying on callers to
restart the translation fetch.

Fixes: e4c7dfac2f1a ("KVM: arm64: nv: Implement HW access flag management in stage-2 SW PTW")
Signed-off-by: Oliver Upton <oupton@kernel.org>
---
 arch/arm64/kvm/at.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/kvm/at.c b/arch/arm64/kvm/at.c
index 6cc5892023dd..4d4285e60fce 100644
--- a/arch/arm64/kvm/at.c
+++ b/arch/arm64/kvm/at.c
@@ -423,6 +423,9 @@ static int walk_s1(struct kvm_vcpu *vcpu, struct s1_walk_info *wi,
 
 		if (wi->s2) {
 			ret = kvm_walk_nested_s2(vcpu, ipa, &s2_trans);
+			if (ret == -EAGAIN)
+				return ret;
+
 			if (ret) {
 				fail_s1_walk(wr,
 					     (s2_trans.esr & ~ESR_ELx_FSC_LEVEL) | level,
-- 
2.47.3