From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f202.google.com (mail-pf1-f202.google.com [209.85.210.202]) (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 DD6274DC53F for ; Wed, 3 Jun 2026 23:07:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780528044; cv=none; b=Ji4JELnbr8Rn0YB6bZWYlj3mxHDA/VTaF1GcdW3q1HmYs7fe8Gku17i3FWBf7BD9JlQmSEtfjznUqgfUcKQsnZPtqFUFYs0xqbON+b2/9n8jyT5b85xNllJoDGFngMCYIYYCq13IMeRRpZLdyMNbJYrG5ix2BwaLeQxXHy0TyrY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780528044; c=relaxed/simple; bh=PZ7XjrbH9m8+YOmUKJ0OBFcX3Uz+SJLiZmTymmSfvX4=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=uq+DKWvI0MzWOU/yGgQhmOAR2nFz5I28KBp2+zkNILUDA8k8xd8bps/80pDSC+DZWslWGQWeG9k9BqJjDOO9FdoSeBHYhc3Anp3XVC20omt6MafEkIQ59zBVDEit8pVA/Kwldk7rrLvypsjEnQQBvZTjHnRRswy9AKwEhiK4AMA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=tIp4wPRk; arc=none smtp.client-ip=209.85.210.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="tIp4wPRk" Received: by mail-pf1-f202.google.com with SMTP id d2e1a72fcca58-8421ffff8a3so91023b3a.2 for ; Wed, 03 Jun 2026 16:07:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1780528042; x=1781132842; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=WIw0X6vfjDVj5H1oM8jPHBHflGwYlG/paQQ4qHvt6so=; b=tIp4wPRkn+nh62PbRLjkM+leBwv2cardu1mLN3BRwbEb3IZcYhm6D0LU2nRUY71FKW CpGjti6cilt1naj3s4BKFSIyyFvZ5notyqkZDOXdm4mcxe+ehPWYV7UwT4YUfC0J7SQt JmNzZKi1MLeNY2zAHx0fIdF2XWWGMk22q2vHWmM4pCGLc2t1+RdLLBfBnks41U5E6Xg/ VqQDAp/emGiSjpmGlSQe2vB4Ldlcx+xlt3u1XBncaHJHA23Em+NKCmfmTJGF/IH1XGg/ 4FKt/RLgVTSTCg3uoGSn667wB/xrs7wCApR2H8Zh1scCj1xsnGVUXLV/drvzWGHVSiMR sJtA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1780528042; x=1781132842; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=WIw0X6vfjDVj5H1oM8jPHBHflGwYlG/paQQ4qHvt6so=; b=oIzfAzuOJpgdG2OF51d2u4SQJqg0PaLtaXHaLoZqcB7WFBe0cFlhdmgg0WkkrPtaos EMBU/zDmwyWOD+Ni+++1hdrCDBNEu0OtgrGBUhyR53mVzKyuezC6U4AviNj8zZNS+WVp nss6v2GTU/KGyjYc8br/7gPTOaaegD1rwkUqdYx52EbpMQXlL8t4Kxbu34APB7nCOktz Uh5PBqXSP3cV6cNZn3MqfqIKQTnsAQ+63a03ol+DI7DmJ4w9fv1H89Gq1h2z0NdIwQtm KAZ9Wn5MqUAfaaOAJ9pSXIhvM25llwW9e+HI3fEij14GViFnHnxsdqY0qG1wBuftCcsY JmWg== X-Forwarded-Encrypted: i=1; AFNElJ/sbNrHufI6br4fMUgYhdRw/3VRFBlR9ZEwXesD0Ips9x9orNP2I74iqXiZLGV7FiXrRwRDyq2vUCzA0Sc=@vger.kernel.org X-Gm-Message-State: AOJu0YwsgOofpZBxHVd/AN7Ov6P4BrjteyI6Tk9F3uyVHkBTIxoOPk3h eoidPRfGER54r3ER+KdMWxAIAz6XSS1XwPodCQB68LkTdwk/Ox2GaojReHvYKcKr9k7aMD3ZrgE KGyshWQ== X-Received: from pfbic3.prod.google.com ([2002:a05:6a00:8a03:b0:842:55c7:d8dc]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:a257:b0:842:4fdd:502e with SMTP id d2e1a72fcca58-84284f2ab82mr5207659b3a.48.1780528041992; Wed, 03 Jun 2026 16:07:21 -0700 (PDT) Reply-To: Sean Christopherson Date: Wed, 3 Jun 2026 16:07:14 -0700 In-Reply-To: <20260603230718.1733483-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260603230718.1733483-1-seanjc@google.com> X-Mailer: git-send-email 2.54.0.1032.g2f8565e1d1-goog Message-ID: <20260603230718.1733483-3-seanjc@google.com> Subject: [PATCH v2 2/6] KVM: x86: Prioritize DR7.GD #DB over #GP due to illegal DR6/7 value From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, "=?UTF-8?q?Carlos=20L=C3=B3pez?=" Content-Type: text/plain; charset="UTF-8" When emulating a MOV DR, specifically a write to DR6 or DR7, treat a #DB due to DR7.GD (General Detect) as higher priority than a #GP due to an illegal value. While neither Intel's SDM nor AMD's APM says anything about the relative priority, empirical testing on Intel and AMD shows that the #DB has higher priority. And for VMX, where the instruction intercept has priority over *all* exceptions, KVM already treats the #DB as having higher priority. Fixes: 3b88e41a4134 ("KVM: SVM: Add intercept check for accessing dr registers") Signed-off-by: Sean Christopherson --- arch/x86/kvm/emulate.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 75cd8b6136aa..4484c5fa19e3 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -3854,11 +3854,16 @@ static int check_dr_write(struct x86_emulate_ctxt *ctxt) { u64 new_val = ctxt->src.val64; int dr = ctxt->modrm_reg; + int rc; + + rc = check_dr_read(ctxt); + if (rc != X86EMUL_CONTINUE) + return rc; if ((dr == 6 || dr == 7) && (new_val & 0xffffffff00000000ULL)) return emulate_gp(ctxt, 0); - return check_dr_read(ctxt); + return X86EMUL_CONTINUE; } static int check_svme(struct x86_emulate_ctxt *ctxt) -- 2.54.0.1032.g2f8565e1d1-goog