From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f201.google.com (mail-pl1-f201.google.com [209.85.214.201]) (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 AFD0419539F for ; Wed, 5 Feb 2025 15:17:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738768632; cv=none; b=SVKuQ9hjMfTadpyoROe+By2nNTJ9NlkonzzRX9msyaisNytJYlnCjCz+2hbpeGBnur8XZfPb6I0foXB6JMxwOpJ2qyZgMESSaEWZXmVg/NYPMkZ5qa7vjGBY5WlyUE6NPJEpYE3HhlysYDV4tM79kt6dL4hoKOXtk7FWWBDxx0M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738768632; c=relaxed/simple; bh=9bQWjyfhOKP94dxGty6MaGQ0+wHvs6zeGJ3FOjx7a4k=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=ODYM34lAcugUs1/sxd1dxuybyUigdUM67aioBFRC4I+iuEWZ6y//dG9pm7rLd7PpOueP7IS/SLdUmszr8oZOLJvK2vRd6PsMMbLNZELzCsWuYoXbDOD/vill08gxogoS/kx0QnHPfYNDNfd9mEtuQQIEAv7rTJixs4r09WwveDo= 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=c26BzEbw; arc=none smtp.client-ip=209.85.214.201 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="c26BzEbw" Received: by mail-pl1-f201.google.com with SMTP id d9443c01a7336-21f1a7dc0e6so27860975ad.3 for ; Wed, 05 Feb 2025 07:17:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1738768630; x=1739373430; darn=lists.linux.dev; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=t0aN/8guITRu30BL0HaWPnLZfgsAxjHGJklJU83lkGw=; b=c26BzEbwD0rC4TomvJE82zd1N/xy6zg5+mMjVOGUh/gciSIglUHVegOc7wbeJhSG6v 8ELi3yS6xIDNz0+q1p6zBVpbl5cKKvG73BXwglDJJjceMPxP5QNIUrzKurqXvA+9Pg8b YMKA5/RSxhid3+piRPArgBG4X0vrda+apwvRognH76ZB2iXV+JsyByeSJPyQJ122vNFL mSv+Kt+XEqFafPcpgo561tyg1OYVFNUqSi6J3AlqHI1OWNopjegMKIkOIjsOju1B3TmW vOyNV1SC1K9rQdUMRYFLkEVAfyPzANnhXmyDl8oYpmownZv6ATV7soawPakT+MJ6dELN FWKQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1738768630; x=1739373430; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=t0aN/8guITRu30BL0HaWPnLZfgsAxjHGJklJU83lkGw=; b=F65WXFzMpmDDrd1UDmnLHyW55EpbOcPMfwpzpnLqWqlT5eDsqC1uhtFZE3TKBe0PSS S1KVNjTQ/iTY+hx7MSlqAu17Fugn8dTc6w7b58qbF8R+xlsTWt+ehO5gXfvScvvGQA1u 3ycfRL44byi6JO0ua5ADhucspxj5sxenaQrON/hns8DAU6XAQ84KUvMwDFetgUL9rWtz apIvDdEM5vBfp6+c6Ies9/64KrSRRoLyyB2KmCvwAqAnnq7P+OAp+ftphGmG/63oICcc Gyx/kDzJ+cM73N0hUnb410n9xmQg4eK9CLehWxNIfav8K5uJPCVf8nlV1AHEBvnIyudn K5oQ== X-Forwarded-Encrypted: i=1; AJvYcCV42u65odY0EJSgiZmqIc0RNHJnjGvFd8kTXcDlUKHznm6VL3i4VuerKySCLFlTAZiN8ybhGoEloa8J@lists.linux.dev X-Gm-Message-State: AOJu0Yx+0Ov3Jb48evrO4+nrHqHfYHPGd+n81w2PmtQxpMoyYnvz7H4N q5rJrrMZRNxovr+OfbBb5yt9AaUxREXqDbJLzYRsZbm3kxLIMljGLwZT9wkGUFfTNVf58curKbK r6Q== X-Google-Smtp-Source: AGHT+IHjO2ZnCRxSz9ckB9UKOIbx0lfEs9B109yICVMG4UQB0RF4tpKtRhegltvZ6NeMdGY988NLUYMrptA= X-Received: from plas19.prod.google.com ([2002:a17:903:2013:b0:21f:467:f8ae]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:228a:b0:21d:cd0c:a1ac with SMTP id d9443c01a7336-21f17df7196mr51828645ad.17.1738768629827; Wed, 05 Feb 2025 07:17:09 -0800 (PST) Date: Wed, 5 Feb 2025 07:17:08 -0800 In-Reply-To: <62b643dd-36d9-4b8d-bed6-189d84eeab59@amd.com> Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <62b643dd-36d9-4b8d-bed6-189d84eeab59@amd.com> Message-ID: Subject: Re: [PATCH v3 3/3] x86/sev: Fix broken SNP support with KVM module built-in From: Sean Christopherson To: Vasant Hegde Cc: Ashish Kalra , pbonzini@redhat.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, thomas.lendacky@amd.com, john.allen@amd.com, herbert@gondor.apana.org.au, davem@davemloft.net, joro@8bytes.org, suravee.suthikulpanit@amd.com, will@kernel.org, robin.murphy@arm.com, michael.roth@amd.com, dionnaglaze@google.com, nikunj@amd.com, ardb@kernel.org, kevinloughlin@google.com, Neeraj.Upadhyay@amd.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, linux-coco@lists.linux.dev, iommu@lists.linux.dev Content-Type: text/plain; charset="us-ascii" On Wed, Feb 05, 2025, Vasant Hegde wrote: > Hi Ashish, > > [Sorry. I didn't see this series and responded to v2]. Heh, and then I saw your other email first and did the same. Copying my response here, too (and fixing a few typos in the process). > > diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c > > index c5cd92edada0..4bcb474e2252 100644 > > --- a/drivers/iommu/amd/init.c > > +++ b/drivers/iommu/amd/init.c > > @@ -3194,7 +3194,7 @@ static bool __init detect_ivrs(void) > > return true; > > } > > > > -static void iommu_snp_enable(void) > > +static __init void iommu_snp_enable(void) > > { > > #ifdef CONFIG_KVM_AMD_SEV > > if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP)) > > @@ -3219,6 +3219,14 @@ static void iommu_snp_enable(void) > > goto disable_snp; > > } > > > > + /* > > + * Enable host SNP support once SNP support is checked on IOMMU. > > + */ > > + if (snp_rmptable_init()) { > > + pr_warn("SNP: RMP initialization failed, SNP cannot be supported.\n"); > > + goto disable_snp; > > + } > > + > > pr_info("IOMMU SNP support enabled.\n"); > > return; > > > > @@ -3318,6 +3326,9 @@ static int __init iommu_go_to_state(enum iommu_init_state state) > > ret = state_next(); > > } > > > > + if (ret && !amd_iommu_snp_en && cc_platform_has(CC_ATTR_HOST_SEV_SNP)) > > > I think we should clear when `amd_iommu_snp_en` is true. That doesn't address the case where amd_iommu_prepare() fails, because amd_iommu_snp_en will be %false (its init value) and the RMP will be uninitialized, i.e. CC_ATTR_HOST_SEV_SNP will be incorrectly left set. And conversely, IMO clearing CC_ATTR_HOST_SEV_SNP after initializing the IOMMU and RMP is wrong as well. Such a host is probably hosed regardless, but from the CPU's perspective, SNP is supported and enabled. > May be below check is enough? > > if (ret && amd_iommu_snp_en) > > > -Vasant > >