From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BD73C46D0A4; Tue, 21 Jul 2026 17:37:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784655465; cv=none; b=e22irmR/3sO1jpRg6Jq+MuoY+b5ns7clbJbzy7u+1G8kRZRSCiKens9Z5R0Jhgm9jXdPB15ztGnajTL9Qv6FXPDQcptob7soIJ+no71dSyIy1bMgSm3sCZtfBlhbmLGEPqsAU8NQ15iRCq/7Jj4atmxvYZkVBZUBe1kAF3RQfOU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784655465; c=relaxed/simple; bh=wOuDYqMoQ72Z2UlMQ7duBhgvXhLieDQBheE+omWQEFA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NpnIYMYoDWe7Ab3CDmTXl3oW/1Y8gjlN7yHwQAnqNMmXJL1HhZf9JjkyqnKjVhy256RCYUwkjwt4633whN74+24G2mbcdatg4kGEvD6g1i4fXNgw+033kNwAwS3yraN7lYRJMMAlzC26VbZ4HtSHo9/3ZVUzbvxzhL/Jon8vjIc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=tMvy328q; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="tMvy328q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D3DC61F000E9; Tue, 21 Jul 2026 17:37:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784655462; bh=GZyJVwJhQZykdzoLF1xulRsEJE0AbQLEAiH7HeuKiLc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=tMvy328q7Ji8beM6n/5d8qmld2lI5F0uQkPNVsAJ4p8WoOXfTpwlivv9Xx/X6KZnJ iEsZECxT8GnZkbzNGV3d/JPO+ujH3aM12SgL3wmH7iQ7FKKZMX8gi9qhaKv8f1fro9 LRqM1T9xJiTfaEeIRF4P/XFSSsb10e5FQlD+bcfk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Borislav Petkov , Suravee Suthikulpanit , Joerg Roedel , Vasant Hegde , Dheeraj Kumar Srivastava , Sasha Levin Subject: [PATCH 6.18 0019/1611] iommu/amd: Use maximum PPR log buffer size when SNP is enabled on Family 0x19 Date: Tue, 21 Jul 2026 17:02:15 +0200 Message-ID: <20260721152515.228743536@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152514.750365251@linuxfoundation.org> References: <20260721152514.750365251@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vasant Hegde [ Upstream commit 1f44aab79bac31f459422dfb213e907bb386509c ] Due to CVE-2023-20585, the PPR log buffer must use the maximum supported size (512K) on Genoa (Family 0x19, model >= 0x10) systems when SNP is enabled, to mitigate a potential security vulnerability. Note that Family 0x19 models below 0x10 (Milan) do not support PPR when SNP is enabled. Hence the PPR log size increase is only applied for model >= 0x10. All other systems continue to use the default PPR log buffer size (8K). Apply the errata fix by making the following changes: - Introduce global new variable (amd_iommu_pprlog_size) to have PPR log buffer size. Adjust variable size for Genoa family. - Extend 'amd_iommu_apply_erratum_snp()' to also set the PPR log buffer size to maximum for Family 0x19 model >= 0x10 when SNP is enabled. - Rename PPR_* macros to make it more readable. Link: https://www.amd.com/en/resources/product-security/bulletin/amd-sb-3016.html Cc: Borislav Petkov Cc: Suravee Suthikulpanit Cc: Joerg Roedel Signed-off-by: Vasant Hegde Tested-by: Dheeraj Kumar Srivastava Signed-off-by: Joerg Roedel Signed-off-by: Sasha Levin --- drivers/iommu/amd/amd_iommu.h | 1 + drivers/iommu/amd/amd_iommu_types.h | 11 ++++++----- drivers/iommu/amd/init.c | 13 ++++++++++++- drivers/iommu/amd/ppr.c | 8 +++++--- 4 files changed, 24 insertions(+), 9 deletions(-) diff --git a/drivers/iommu/amd/amd_iommu.h b/drivers/iommu/amd/amd_iommu.h index 57d7f3faa98c6e..ef397c5a2c4ab2 100644 --- a/drivers/iommu/amd/amd_iommu.h +++ b/drivers/iommu/amd/amd_iommu.h @@ -12,6 +12,7 @@ #include "amd_iommu_types.h" extern int amd_iommu_evtlog_size; +extern int amd_iommu_pprlog_size; irqreturn_t amd_iommu_int_thread(int irq, void *data); irqreturn_t amd_iommu_int_thread_evtlog(int irq, void *data); diff --git a/drivers/iommu/amd/amd_iommu_types.h b/drivers/iommu/amd/amd_iommu_types.h index bdd6c38ddfec9b..2494b1958117b2 100644 --- a/drivers/iommu/amd/amd_iommu_types.h +++ b/drivers/iommu/amd/amd_iommu_types.h @@ -257,11 +257,12 @@ #define EVTLOG_LEN_MASK_MAX (0xFULL << EVTLOG_SIZE_SHIFT) /* Constants for PPR Log handling */ -#define PPR_LOG_ENTRIES 512 -#define PPR_LOG_SIZE_SHIFT 56 -#define PPR_LOG_SIZE_512 (0x9ULL << PPR_LOG_SIZE_SHIFT) -#define PPR_ENTRY_SIZE 16 -#define PPR_LOG_SIZE (PPR_ENTRY_SIZE * PPR_LOG_ENTRIES) +#define PPRLOG_ENTRY_SIZE 0x10 +#define PPRLOG_SIZE_SHIFT 56 +#define PPRLOG_SIZE_DEF SZ_8K /* 512 entries */ +#define PPRLOG_LEN_MASK_DEF (0x9ULL << PPRLOG_SIZE_SHIFT) +#define PPRLOG_SIZE_MAX SZ_512K /* 32K entries */ +#define PPRLOG_LEN_MASK_MAX (0xFULL << PPRLOG_SIZE_SHIFT) /* PAGE_SERVICE_REQUEST PPR Log Buffer Entry flags */ #define PPR_FLAG_EXEC 0x002 /* Execute permission requested */ diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c index 64964bb5ce0d36..6e5efc340c83e4 100644 --- a/drivers/iommu/amd/init.c +++ b/drivers/iommu/amd/init.c @@ -133,6 +133,7 @@ struct ivhd_entry { } __attribute__((packed)); int amd_iommu_evtlog_size = EVTLOG_SIZE_DEF; +int amd_iommu_pprlog_size = PPRLOG_SIZE_DEF; /* * An AMD IOMMU memory definition structure. It defines things like exclusion @@ -3411,6 +3412,16 @@ static void amd_iommu_apply_erratum_snp(void) amd_iommu_evtlog_size = EVTLOG_SIZE_MAX; pr_info("Applying erratum: Increase Event log size to 0x%x\n", amd_iommu_evtlog_size); + + /* + * Set PPR log buffer size to max. + * (Family 0x19, model < 0x10 doesn't support PPR when SNP is enabled). + */ + if (boot_cpu_data.x86_model >= 0x10) { + amd_iommu_pprlog_size = PPRLOG_SIZE_MAX; + pr_info("Applying erratum: Increase PPR log size to 0x%x\n", + amd_iommu_pprlog_size); + } #endif } @@ -4071,7 +4082,7 @@ int amd_iommu_snp_disable(void) if (ret) return ret; - ret = iommu_make_shared(iommu->ppr_log, PPR_LOG_SIZE); + ret = iommu_make_shared(iommu->ppr_log, amd_iommu_pprlog_size); if (ret) return ret; diff --git a/drivers/iommu/amd/ppr.c b/drivers/iommu/amd/ppr.c index e6767c057d01fa..1f8d2823bea42c 100644 --- a/drivers/iommu/amd/ppr.c +++ b/drivers/iommu/amd/ppr.c @@ -20,7 +20,7 @@ int __init amd_iommu_alloc_ppr_log(struct amd_iommu *iommu) { iommu->ppr_log = iommu_alloc_4k_pages(iommu, GFP_KERNEL | __GFP_ZERO, - PPR_LOG_SIZE); + amd_iommu_pprlog_size); return iommu->ppr_log ? 0 : -ENOMEM; } @@ -33,7 +33,9 @@ void amd_iommu_enable_ppr_log(struct amd_iommu *iommu) iommu_feature_enable(iommu, CONTROL_PPR_EN); - entry = iommu_virt_to_phys(iommu->ppr_log) | PPR_LOG_SIZE_512; + entry = iommu_virt_to_phys(iommu->ppr_log); + entry |= (amd_iommu_pprlog_size == PPRLOG_SIZE_DEF) ? + PPRLOG_LEN_MASK_DEF : PPRLOG_LEN_MASK_MAX; memcpy_toio(iommu->mmio_base + MMIO_PPR_LOG_OFFSET, &entry, sizeof(entry)); @@ -201,7 +203,7 @@ void amd_iommu_poll_ppr_log(struct amd_iommu *iommu) raw[0] = raw[1] = 0UL; /* Update head pointer of hardware ring-buffer */ - head = (head + PPR_ENTRY_SIZE) % PPR_LOG_SIZE; + head = (head + PPRLOG_ENTRY_SIZE) % amd_iommu_pprlog_size; writel(head, iommu->mmio_base + MMIO_PPR_HEAD_OFFSET); /* Handle PPR entry */ -- 2.53.0