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 4226022097 for ; Fri, 31 Jan 2025 01:48:24 +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=1738288106; cv=none; b=MtbqPLnelFRF6BfKqR0xMxYOB6vtuH9q6YKPalnuAMuxXCJkMfXP/RGvyqb17+8lW4HNWOdgJxdd5T9NB9CYnTXQrduijGM4F+BJ0D+pniVVcfoIjUK2qpNknn+rw0BPS3ZLHqEBPOPgs+tUsPCwr7C1Krp6Ppfw4amC9TQ36ac= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738288106; c=relaxed/simple; bh=PCcWp1tjtTTwT+4T+gwNe8f1pHXDJ+jDQQs7L3JrJJQ=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=uA66EEX7nvh9HXu+QI/nTz0hpQcb014FcGLV97kqyJ00Pnr2TkBp/WuITQCNyOsv8wQ+wQldm/+0W5H4PE2/RdAT4DGpV6ijVLW/CcSuxo3dqvebFZ5cLu/yNQxHBfGvia0jK5FD/i/kqupdFqyd9PEbrppEJPwvV0SdIp200nc= 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=aBFs5JFV; 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="aBFs5JFV" Received: by mail-pl1-f201.google.com with SMTP id d9443c01a7336-2163dc0f689so43997325ad.1 for ; Thu, 30 Jan 2025 17:48:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1738288103; x=1738892903; 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=yk4T/kfqEFgVa3SrODaXARdMdIV0x31oxIDNkWjd6DU=; b=aBFs5JFVyUKZCjzbQmfjNBLTWNR/N8ztsVCvcuxiWnBvpxZwfDqQO/Ax5rr/TtB+lg T21AOFth6TIJQSyRz/A4bYsEm3Lo3xfVoAp9lzOX26xxHRRcNKzyG6JgW35UbqOweC+9 EjJT5XW2/P0dy/Desinz8aypsDAUUEIWTdDvV5ZKcufRl6zTjVgzJrZhieYcfbpViYaC 1YgmrEfBQlsPqYzzahthFLrEPtNEFWJelPRgzT8EshgVgvEDpNbiVpf/MEqOV9NjbsxF fO/HJkwl4S43fyBrObadrcEXX+y55Lfmc4niUkfvtTKb5SlFRnWkoPdBA6NNQd/uG05K Qd+w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1738288103; x=1738892903; 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=yk4T/kfqEFgVa3SrODaXARdMdIV0x31oxIDNkWjd6DU=; b=BXb1fszFqjHbg/kmgYukHluaw/smTUJMqYjgsC/8RcclRoldpmAg9HyNPBGzngR7jn H34Cc2Vb/nQX1m/ZdRdfGIdz6ONu/bdPC9vwXxZDQq6Hvt+Wo6g9snIReGS/5/VMxf2y fUzh1xzC13L8N5EHFLv9ia0kuTHMwO0Ui+33M1GaUxeJWU/hGpgF5Zz7SrodNSo/K+1+ dw0ZfnZayVQq+Gg7gbfXksMtKiOYuorZYQJN4OnkGiukEfAH4cvjkWiSYhINxmCNy560 Fv3jMYnt/ux47HzxnDNfgyMBcBWYV7NpIvK3R18UvQQP5kiyWtWDOnscwQsZQSAJdEf/ YyiQ== X-Forwarded-Encrypted: i=1; AJvYcCUFF+wJIqe+XIMZsvPy6+cigjg9kjEJyDYpNibMFzlQy9XKiSEUNk9bmliIqNVESj44Guf447+Zk7Do@lists.linux.dev X-Gm-Message-State: AOJu0YwXhwilm1jDfmFv9Lsm2VusyascBWdQphFDyLKoOv9A9DuhBoIx dmlSAjK2pA1S/nV+cmhrb+ZDV/jlamL2CsG0LZpxfrazb4TFYcb3EccLsQ8plrXy2VodYtdsUT0 5tQ== X-Google-Smtp-Source: AGHT+IG0aBeCk8/iEUAOZ9Ro4ZQRn21EJE6cjItE25bpHK7iUdp9q2QgGNTaw88LaidLTqtzkYVxy3WfYW8= X-Received: from pjbso10.prod.google.com ([2002:a17:90b:1f8a:b0:2ef:82c0:cb8d]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:f70c:b0:21d:3bee:990c with SMTP id d9443c01a7336-21dd7de15b4mr143430755ad.42.1738288103586; Thu, 30 Jan 2025 17:48:23 -0800 (PST) Date: Thu, 30 Jan 2025 17:48:22 -0800 In-Reply-To: Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: Message-ID: Subject: Re: [PATCH v2 4/4] iommu/amd: Enable Host SNP support after enabling IOMMU SNP support From: Sean Christopherson To: Ashish Kalra Cc: 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 Fri, Jan 31, 2025, Ashish Kalra wrote: > From: Sean Christopherson > > This patch fixes the current SNP host enabling code and effectively SNP ^^^^^^^^^^ > --- > drivers/iommu/amd/init.c | 18 ++++++++++++++---- > 1 file changed, 14 insertions(+), 4 deletions(-) > > diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c > index c5cd92edada0..ee887aa4442f 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) If you're feeling nitpicky, adding "__init" could be done in a separate patch. > { > #ifdef CONFIG_KVM_AMD_SEV > if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP)) > @@ -3219,6 +3219,11 @@ static void iommu_snp_enable(void) > goto disable_snp; > } > > + 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; > > @@ -3426,18 +3431,23 @@ void __init amd_iommu_detect(void) > int ret; > > if (no_iommu || (iommu_detected && !gart_iommu_aperture)) > - return; > + goto disable_snp; > > if (!amd_iommu_sme_check()) > - return; > + goto disable_snp; > > ret = iommu_go_to_state(IOMMU_IVRS_DETECTED); > if (ret) > - return; > + goto disable_snp; This handles initial failure, but it won't handle the case where amd_iommu_prepare() fails, as the iommu_go_to_state() call from amd_iommu_enable() will get short-circuited. I don't see any pleasant options. Maybe this? diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c index c5cd92edada0..436e47f13f8f 100644 --- a/drivers/iommu/amd/init.c +++ b/drivers/iommu/amd/init.c @@ -3318,6 +3318,8 @@ 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)) + cc_platform_clear(CC_ATTR_HOST_SEV_SNP); return ret; } Somewhat of a side topic, what happens if the RMP is fully configured and _then_ IOMMU initialization fails? I.e. if amd_iommu_init_pci() or amd_iommu_enable_interrupts() fails? Is that even survivable? > > amd_iommu_detected = true; > iommu_detected = 1; > x86_init.iommu.iommu_init = amd_iommu_init; > + return; > + > +disable_snp: > + if (cc_platform_has(CC_ATTR_HOST_SEV_SNP)) > + cc_platform_clear(CC_ATTR_HOST_SEV_SNP); > } > > /**************************************************************************** > -- > 2.34.1 >