From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-185.mta0.migadu.com (out-185.mta0.migadu.com [91.218.175.185]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D0346347FC4 for ; Mon, 22 Jun 2026 19:07:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.185 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782155230; cv=none; b=Eyjb8OkVg6bxSN5x8RrzoqJp1tG1t3BMfQosbjrSxdWNDwUV2dUVoZuEL07DMCkuMSU1MeWKRaRdYJWvr+es3ii3S45SuzcATflUX/avpsIEO3c+lttDq0XYpSpdllfL3q3MYJK7R4TaRwFtOq9KmCHOvH/gA6ozUH/xv0e0KPU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782155230; c=relaxed/simple; bh=EZk09mqwniyPaFY6x/GnurTL+HGeh3ghHZEqPVduw8w=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=iaZ9LXKDQy16aHGKJkesWHh2w/uobWSOpbwhFdza0ISr7VZlWVKxO2TMgJ//i0KGSpjhSyNgZlqpwKwJf31oX9ku/EN/jjnmhpbG9f069Y4Z300+Wa/7B4Ili9rrwqt3t+gvQHIto3U3hn+SooJtc5N6B+0eCKikE3Ew2K/qPjI= 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=XDXKXiii; arc=none smtp.client-ip=91.218.175.185 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="XDXKXiii" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1782155227; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6FUoNtrIxitio2ZcQ79fK9DlQrFdcFNyScyGhi0wHX0=; b=XDXKXiiifWQNZIr/g1YmsSsbeyBAfeo6+8/OO+eifiMSpBlOJRfGQRJu9UFoVJQi1Ix0XX tdjh/tgmDDXv1UEXGI1ycypC4Wf8M0PJSrFynOimdNkHlJ3vfM99+bN0aw0d/o4kHuYwZL uxDgMv+GHevA/N26axb2YqEWvgF0AaY= From: Fuad Tabba To: Marc Zyngier , Oliver Upton Cc: Joey Gouly , Suzuki K Poulose , Zenghui Yu , Steffen Eiden , Catalin Marinas , Will Deacon , Shuah Khan , Christoffer Dall , Victor Kamensky , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH 1/2] KVM: arm64: Fix sign-extension of MMIO loads Date: Mon, 22 Jun 2026 20:07:00 +0100 Message-Id: <20260622190701.2039766-2-fuad.tabba@linux.dev> In-Reply-To: <20260622190701.2039766-1-fuad.tabba@linux.dev> References: <20260622190701.2039766-1-fuad.tabba@linux.dev> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT A sign-extending load from MMIO (LDRSB, LDRSH, LDRSW) delivers a zero-extended value: in kvm_handle_mmio_return(), vcpu_data_host_to_guest() masks the data to the access width after sign-extension, stripping the sign bits. Move vcpu_data_host_to_guest() ahead of sign-extension so the width mask runs first. trace_kvm_mmio() moves with it and keeps reporting the raw access-width data. Fixes: b30070862edbd ("ARM64: KVM: MMIO support BE host running LE code") Signed-off-by: Fuad Tabba --- arch/arm64/kvm/mmio.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kvm/mmio.c b/arch/arm64/kvm/mmio.c index e2285ed8c91de..d1c3a352d5a22 100644 --- a/arch/arm64/kvm/mmio.c +++ b/arch/arm64/kvm/mmio.c @@ -126,6 +126,10 @@ int kvm_handle_mmio_return(struct kvm_vcpu *vcpu) len = kvm_vcpu_dabt_get_as(vcpu); data = kvm_mmio_read_buf(run->mmio.data, len); + trace_kvm_mmio(KVM_TRACE_MMIO_READ, len, run->mmio.phys_addr, + &data); + data = vcpu_data_host_to_guest(vcpu, data, len); + if (kvm_vcpu_dabt_issext(vcpu) && len < sizeof(unsigned long)) { mask = 1U << ((len * 8) - 1); @@ -135,9 +139,6 @@ int kvm_handle_mmio_return(struct kvm_vcpu *vcpu) if (!kvm_vcpu_dabt_issf(vcpu)) data = data & 0xffffffff; - trace_kvm_mmio(KVM_TRACE_MMIO_READ, len, run->mmio.phys_addr, - &data); - data = vcpu_data_host_to_guest(vcpu, data, len); vcpu_set_reg(vcpu, kvm_vcpu_dabt_get_rd(vcpu), data); } -- 2.39.5