From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta0.migadu.com (out-1.mta0.migadu.com [91.218.175.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4F1814E780C for ; Mon, 28 Sep 2026 15:25:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.1 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790609145; cv=none; b=uyJquDr/2D9aOtB1u+Zihj5ZMyXBqBRN6GxRZwhM9jwGbiHnXssm+vhde2OpDi5DS6Fbb0xTdloLVRnMWNh+N5nOd6iiElOdoVzrySgwBDBRUIVl6aFM7pNYBqlwzY0AS7e9jAIKeJdOQwTwts2X4AXpUmV7ngIL5B14AV7k/1Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790609145; c=relaxed/simple; bh=4/J0Nyoe1OYgfmPuqQeHxdHnDki4Fb0pleDZiROcdZs=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=INVCAVineNBL4qokWOJpT8rGZd15Z2tvEUKyW8Verx9J5NDoUSoamo9kw0mSOH2AgOUDg8KARr8+j0K8vGLU7LbObcbZhudJvyzVd0bBgES1LPyzMs8s/WAYsFU5q1RiGVStU30xh5enwx86IIQvDOy1zQiPUH9+PrUxHm9ggr0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=SsvceiRJ; arc=none smtp.client-ip=91.218.175.1 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="SsvceiRJ" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=4/J0Nyoe1OYgfmPuqQeHxdHnDki4Fb0pleDZiROcdZs=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1790609141; v=1; x=1791213941; b=SsvceiRJbFyX6mPSL0oOeT56sEHwbENj2tjz7Agj89GXhKICj5deuP+EJ7D+ucln/cWl0MIF HhBneBYyTdjTtjUNE+mwDIPzr7LFKBgWHLVbCv2cmpjvSdvwze6quNlxhHKCoqkRI7Nj1g7n2ie XlpsJJA6YzLMNrLtzR3VcyLc= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id de1ed31cb70c73c5; Mon, 28 Sep 2026 15:25:40 +0000 X-Mizu-Trace-ID: de1ed31cb70c73c5 X-Migadu-Flow: FLOW_OUT From: Fuad Tabba To: Marc Zyngier , Oliver Upton , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org Cc: Joey Gouly , Suzuki K Poulose , Zenghui Yu , Steffen Eiden , Catalin Marinas , Will Deacon , Mark Rutland , Jing Zhang , Karl Mehltretter , Fuad Tabba , kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v1 04/10] KVM: arm64: nv: Return a failed stage-2 descriptor read as a fault Date: Mon, 28 Sep 2026 16:25:01 +0100 Message-Id: <20260928152507.2116110-5-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20260928152507.2116110-1-fuad.tabba@linux.dev> References: <20260928152507.2116110-1-fuad.tabba@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When KVM walks an L1 guest's stage-2 tables and can't read a descriptor, for example because the guest points a table at an IPA with no memslot, it sets a synchronous external abort on the walk but returns the -EFAULT from kvm_read_guest(). As with an invalid VTCR_EL2, KVM then leaves AT S12E{0,1}{R,W} unretired, so the guest retries it forever. On an L2 abort, KVM injects the abort and returns -EFAULT from KVM_RUN. Return 1, as the walk already does when it can't update a descriptor, leaving -EAGAIN from a descriptor race as its only negative return. The AT then retires with the external abort in PAR_EL1, which is what a stage-1 walk records for a descriptor it can't read. Fixes: fd276e71d1e7b ("KVM: arm64: nv: Handle shadow stage 2 page faults") Fixes: 92c6443222ca4 ("KVM: arm64: Propagate PTW errors up to AT emulation") Signed-off-by: Fuad Tabba --- arch/arm64/kvm/nested.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c index a67be19e73250..f9a2e50c0b567 100644 --- a/arch/arm64/kvm/nested.c +++ b/arch/arm64/kvm/nested.c @@ -304,7 +304,7 @@ static int walk_nested_s2_pgd(struct kvm_vcpu *vcpu, phys_addr_t ipa, ret = read_guest_s2_desc(vcpu, paddr, &desc, wi); if (ret < 0) { out->esr = ESR_ELx_FSC_SEA_TTW(level); - return ret; + return 1; } new_desc = desc; -- 2.39.5