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 ADB883D667D for ; Fri, 12 Jun 2026 23:01:20 +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=1781305282; cv=none; b=nkJ/BXSY1fJcCTzzgx6zuFQ7jXHcFwz8QfJd11rlsfvr6QGo1a0aS9OjbywBoB5L20bk4kEYrM2WDn5x7mCrKbtQNSwDm7OWyoCyPWNXWRXR+onMfu5XA7xkoIgQ27xCz18cB6vQhEZNhkNMFeUQQ32dTzzV0BHaIG9OK/MJDcA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781305282; c=relaxed/simple; bh=DKAqswpPaExUn02wUL+NOxMfuWixP3sOTmVCG3euVIk=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=OUsgl0bfsQTC7aqyPUoohOeehx048LBb3lTh2KhL4cYfm0zQ1gHSvVOx0WxVfnojBl4ekSWQcckzsqvuUciWEUUMz6lCWC8xEjDHWdgceEV+Q/xCP3pIMM5lvgBFT0tV/S0x86avQTxhEZBgZ9EuVatnHh2CFjow9Fjo4PPOQ+Q= 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=nh32vvNR; 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="nh32vvNR" Received: by mail-pf1-f202.google.com with SMTP id d2e1a72fcca58-842688fa7b8so2379789b3a.0 for ; Fri, 12 Jun 2026 16:01:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1781305280; x=1781910080; 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=J359yHegu9UkwwiKsAhLDZGnRJ5TMvYWdSC1Vkojkx4=; b=nh32vvNRDnkBXvEU67+vZlEDQVNqMEaVq23Zuns5gefbqbi3o+EuXBitCkkYs05ZpI ziDip4am++2OTjw6+r6bqKa/iYvpbmzHXxN4jUrnm9nhzPboSPEJWbWyIUn3hFo9P2JW Ue+Lc1Pl7y9k5W37U8V+SCOPmw7LP1K8UdHNo8rTFIlRB5BPq5yk/UfPreyXtJjDiK2Z 1b3+3A3MobNo+hw2Z3MCInZ8C6Bh0E2+7EiLdrjnc7rR4qpZO78Ba1J9MULLPs3fLq86 i1xODl9bXrUSRTty1mDRZ0d4kitANTts2fuW6OMvKBX82S5rEDiAqz840rVU6SpqtLYT KDbA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1781305280; x=1781910080; 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=J359yHegu9UkwwiKsAhLDZGnRJ5TMvYWdSC1Vkojkx4=; b=E4JLYJsuQvzjJz0zpOp2Js+eVsAHxKW8q3YhG0k0dddo0GViS0yvylnIMlM+7KR9ub LmfEIc9RF8X9Du2KmLesZTdC6TIIfWe3gVuIqPHirTUO+t98J5/UOtphJ5wnjAEt/CJK wPhTCwtqBg+q7cs/EpZsyBu3mf3zUmO4ITVQf5QXaSCbuAbakpHd4CtqDd/6mINysDEz SnbeA7YzMoucKhImQSNbRx0KgtSTFQFZSBVqCVNfFcZIz94h3tksS2CDFZgp4VNwj4/i bVQ6NFM0CFAWrek8BKjg9AonUixL1QPpA/sQlxZAhaSaYipkbquwb2vsi+Dy42227cJc OCkA== X-Forwarded-Encrypted: i=1; AFNElJ9R/gkDgd3kjUzazBmffIdYD7DcfmZ0pXCuSlHngaKCSaI7eX+K0CL3WNy+89k6QGqEWQYElyecrrVUuTc=@vger.kernel.org X-Gm-Message-State: AOJu0Ywnf0aNKKq+s98/43PQBYI0TV8Sqi+0ZkyeOzRgQr+A3N/8zsee osccjfiFX6Vt+W+1usdkgxvjocuOzh96Xcj2hnx9Kc3G+QYqt/t4gx2rEdNgRW/BViceYgCrFp7 xXTtXXw== X-Received: from pfbfb1.prod.google.com ([2002:a05:6a00:2d81:b0:83f:420:c568]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:2395:b0:842:499d:450e with SMTP id d2e1a72fcca58-843497500b4mr4466895b3a.20.1781305279654; Fri, 12 Jun 2026 16:01:19 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 12 Jun 2026 16:01:07 -0700 In-Reply-To: <20260612230113.684301-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260612230113.684301-1-seanjc@google.com> X-Mailer: git-send-email 2.54.0.1136.gdb2ca164c4-goog Message-ID: <20260612230113.684301-3-seanjc@google.com> Subject: [PATCH v3 2/8] 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?=" , "Maciej W . Rozycki" 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. Cc: Maciej W. Rozycki 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) -- 2.54.0.1136.gdb2ca164c4-goog