From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-104.mta1.migadu.com [95.215.58.104]) (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 5599444239E for ; Mon, 17 Aug 2026 16:06:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.104 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786982808; cv=none; b=ru0brxaZZtWl6uH962vv2sWDwV2tjzWyxf3B6QNzDiQHmMD73VwoEJDxwrgCSbF4iPX7+jMLmu7akEEE2mY4otthhjaRcYUi/mZhoeQmCWu0EhbC2xya2LD31wpLyVIg2yVJgnG05+jxl1uWKmUC73tPVvNA8tVN6sv4tzLVn00= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786982808; c=relaxed/simple; bh=CgqZe8Bz0XwM99muFJKusVR1o4fnvZ8HiDN7HUnr2rw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BgvJ3uubFizCniWKjzt52/7gxxoAmgAWJH/ERsXj2qDO6BGloeNCWB4EklHlDAyHsxNorg2cHxHy07x3aTFktiP+t44+FbQDA5zXxzFxOgKDYESFuPeiA2qpoH2dUG0hvgayZUSmMT2zCh2DIXGRDQF8JzytPU7eYqSfecDjCzU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=WVasJwAc; arc=none smtp.client-ip=95.215.58.104 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="WVasJwAc" X-Envelope-To: iommu@lists.linux.dev DKIM-Signature: a=rsa-sha256; bh=CgqZe8Bz0XwM99muFJKusVR1o4fnvZ8HiDN7HUnr2rw=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1786982805; v=1; x=1787587605; b=WVasJwAcCohL5sID0YzwEc3F5D+dXtNXHXGueVcpIteC3z8w/9bcGI6gnqG/UibAPRZUcSDB m9UOO130pO+qx/vjCJ2CZ468EqnZ+7qeOOvSn01I9T78BsPLrXMaZUVMKNQEvNIztG9yicaY7fD P3r/HdqOatjFTowsLSAniTlc= X-Envelope-To: iommu@lists.linux.dev Received: from localhost (2a03:2880:10ff:5c::) by mta12.migadu.com with ESMTPS id 181de17a528cb54c; Mon, 17 Aug 2026 16:06:45 +0000 X-Migadu-Flow: FLOW_OUT From: Usama Arif To: Vasant Hegde Cc: Usama Arif , iommu@lists.linux.dev, joro@8bytes.org, will@kernel.org, robin.murphy@arm.com, suravee.suthikulpanit@amd.com, bp@alien8.de, Joerg Roedel , samuelcrossley@gmail.com, "Srivastava, Dheeraj Kumar" Subject: Re: [PATCH 0/2] iommu/amd: Use MAX buffer size when SNP is enabled on Family 0x19 Date: Mon, 17 Aug 2026 09:06:41 -0700 Message-ID: <20260817160642.418302-1-usama.arif@linux.dev> X-Mailer: git-send-email 2.53.0 In-Reply-To: <697be383-2de0-4c6b-91c1-9887d23ddc9b@amd.com> References: Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Thu, 13 Aug 2026 19:28:55 +0530 Vasant Hegde wrote: > Usama, > > On 8/13/2026 6:48 PM, Usama Arif wrote: > > [You don't often get email from usama.arif@linux.dev. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ] > > > > On Mon, 20 Apr 2026 08:42:02 +0000 Vasant Hegde wrote: > > > >> This series addresses CVE-2023-20585 [1] by increasing the AMD IOMMU > >> Event log and PPR log buffer sizes to the maximum supported value (512K) > >> on affected CPU families when SNP is enabled. > >> > >> Use MAX buffer size when SNP is enabled on Milan/Genoa. Impacted buffers: > >> - Milan : Event log (PPR/GALog is not supported when SNP is enabled) > >> - Genoa : Event and PPR log (GALog is not supported when SNP is enabled) > >> > > > > Hi, > > > > This series seems to break kexec in our production on Milan hosts with SEV enabled. > > This is on the 6.18.43 stable kernel backport. > > Do you have dmesg? > > > > > If on top of 6.18.43 release, we revert the 2 commits, i.e. > > Revert "iommu/amd: Use maximum PPR log buffer size when SNP is enabled on Family 0x19" > > Revert "iommu/amd: Use maximum Event log buffer size when SNP is enabled on Family 0x19" > > > > kexec starts working again. > > > Could you help in fixing this issue? > > Sure. We will try to reproduce it internally and get back to you. Hi, Just following up, were you able to reproduce this? I was able to trace down the hang to this do while loop [1]. Could this be a firmware bug? We are currently running 1.53 (below shows up in the dmesg). [ 22.245942] ccp 0000:41:00.1: SEV-SNP API:1.53 build:5 [ 22.308933] ccp 0000:41:00.1: SEV API:1.53 build:5 [1] https://elixir.bootlin.com/linux/v7.2/source/arch/x86/virt/svm/sev.c#L1017 Thanks, Usama > > -Vasant > >