From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f202.google.com (mail-pl1-f202.google.com [209.85.214.202]) (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 7C60E38C402 for ; Tue, 26 May 2026 15:55:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779810951; cv=none; b=HEdp4H4WHDpjxwXDNYjNlDtg16yfueCuw7ijLQdiKmj3232WpF95mV1GsEk/HAf3oj0FmOEMNj47uwmv9eilr9qzjtZxZbsdZS9DTVRS6qPwL233k8dikYRPvMv9T/ZLXRBjD6BKK6qpRsgEMmwQizgvu20V2lgmfbPJTCqbRJ4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779810951; c=relaxed/simple; bh=vlcIXZfpF5z544D6f/NmQwNsL7FDGdksfw3NZhpVsGk=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=eWohOE6d54AtN6LP1t9y9q4F58WDoVLuInk6IKhHP2EbGqyYH89J3fxJcxCjlIgPVTW/fipTXWLQWy8DHzhKA9JLs6wBOSgTyGEL0QGYclc8ByH/xCVX9eT4KeUzse6rynO55Z26AHjkUZMbK7sL1RVRx47T+oX2mVB/AdezRI8= 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=v6EsR8dR; arc=none smtp.client-ip=209.85.214.202 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="v6EsR8dR" Received: by mail-pl1-f202.google.com with SMTP id d9443c01a7336-2babc42244aso4363865ad.3 for ; Tue, 26 May 2026 08:55:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1779810950; x=1780415750; 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=hySHD8b2TDWrlaxMGeF1pIvJSXR1GuivjeYjS/HSokw=; b=v6EsR8dRziXpYUOY95mWd7cZr1U2StqxGOUNffPD/vwWLPqOh9EfmU46ko4d1S5q2M vRaAHxaz4G0Ax9ZEmRurn3yDei8xkTwVt6AiC+1hV70r4h0JIaSw4IqclWmbbQvfoBkH k3YI92nNkivtEI3ujWNrdLuWO5I24a7tVSaIJsraMtXVA9pouOhDdWZp4tYJ544qEKW2 6Lx++Eh8vIuFqCeNPFYFDjX+BzzZRJ+pc+Bff7YX1c/8vgJvVQlbmBXIWtNO1tkYHY9O DqhsXz/SAHaLKp66UNP7OdhFyEra676mucZCztC79YkAmiYwD7yz2DOG+I5acbBHy8UQ 58nA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779810950; x=1780415750; 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=hySHD8b2TDWrlaxMGeF1pIvJSXR1GuivjeYjS/HSokw=; b=J39xhV7SaCLiBYck4N1H/FeR5JDIIKINPbbQfLIbA5jCgtNniRBkGLAcOAgH3wcPUO 2VEa16+xmqyrOmAZWKtejP5aZAGDTTO3YmFX44/klH4hGzP++Oh8UWRdpGWH0Zpg1+4h veFI2L3mM+mKAtRVCNwBY2O7wnAklDjl6tQIm1ZeSjAIp2P+KTNBS/HRPnnKbeJyDqiD fd7UN+Bkkx2GBRNZiEO9QFp5am9EmSVAW8Y8qxpBsF5EP6zpfSRAQYw+edq9VfNpLSYL E7t1Z17m4aXMVCb9d5kA5GY2dH4Z62rIq9qPjexxya1O+pN5d2dbFC/Q9NLc9WqT1wND yTFg== X-Forwarded-Encrypted: i=1; AFNElJ8415P5Ox6fjPFwD1I8tBulyuacB/Mb90HY56bL5SBDESVNoy7F4V2w95q327yaaQeaKLpdHcLsXZqU@lists.linux.dev X-Gm-Message-State: AOJu0YxaWWxFhenlEMFKMsiHVE9RsrkvuSpahAqv4BKHyqS3LDyOvcHC oEqCWtgJ6xuGuSRnW6q9n4T6F9dv7DbsKrHReuP9MnJA8bVrg6DLGyHAfa1C9h/ITKRM3+crShB waN2XlA== X-Received: from plnz8.prod.google.com ([2002:a17:902:8348:b0:2bd:7eaa:5d77]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:3b87:b0:2ba:3e2f:6883 with SMTP id d9443c01a7336-2beb05d9f8cmr216024545ad.19.1779810949754; Tue, 26 May 2026 08:55:49 -0700 (PDT) Date: Tue, 26 May 2026 08:55:49 -0700 In-Reply-To: <20260522-fix-sev-gmem-post-populate-v2-4-3f196bfad5a1@google.com> Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260522-fix-sev-gmem-post-populate-v2-0-3f196bfad5a1@google.com> <20260522-fix-sev-gmem-post-populate-v2-4-3f196bfad5a1@google.com> Message-ID: Subject: Re: [PATCH v2 4/5] KVM: SNP: Fix kunmap_local() unmapping order From: Sean Christopherson To: Ackerley Tng Cc: Paolo Bonzini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Kiryl Shutsemau , Rick Edgecombe , Vishal Annapurve , Yan Zhao , Michael Roth , Isaku Yamahata , Chao Peng , Xiaoyao Li , Zongyao Chen , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-coco@lists.linux.dev, Yu Zhang , Fuad Tabba Content-Type: text/plain; charset="us-ascii" Similar comment on the shortlog as patch two. "Fix the order" tells the reader nothing useful, other than the author of the patch thought there was a bug. KVM: SEV: Unmap local kmaps in LIFO order, per highmem requirements No need for a new version, I'll massage when applying. On Fri, May 22, 2026, Ackerley Tng wrote: > Mappings created with kmap_local_page() or kmap_local_pfn() must be > unmapped in the reverse order they were acquired, following a LIFO > (last-in, first-out) stack-based approach. > > In sev_gmem_post_populate(), src_vaddr is mapped first and dst_vaddr is > mapped second. The current code incorrectly calls kunmap_local() for > src_vaddr before dst_vaddr. > > Swap the kunmap_local() calls to ensure the mappings are released in the > correct order. It's worth calling out that this is completely benign since SNP is 64-bit only.