From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	Li RongQing <lirongqing@baidu.com>,
	Vasant Hegde <vasant.hegde@amd.com>,
	Ankit Soni <Ankit.Soni@amd.com>,
	Joerg Roedel <joerg.roedel@amd.com>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.18 0832/1250] iommu/amd: Add NUMA node affinity for IOMMU log buffers
Date: Thu, 17 Sep 2026 16:10:27 +0100
Message-ID: <20260917151614.497711203@linuxfoundation.org>
In-Reply-To: <20260917151551.901433442@linuxfoundation.org>
References: <20260917151551.901433442@linuxfoundation.org>
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6.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Li RongQing <lirongqing@baidu.com>

[ Upstream commit 1e0c8d6b695217cb0b16f13e31c7f08b453097b4 ]

Currently, PPR Log and GA logs for AMD IOMMU are allocated using
iommu_alloc_pages_sz(), which does not account for NUMA affinity. This can
lead to remote memory access latencies if the memory is allocated on a
different node than the IOMMU hardware.

Switch to iommu_alloc_pages_node_sz() to ensure that these data structures
are allocated on the same NUMA node as the IOMMU device. If the node
information is unavailable, it defaults to NUMA_NO_NODE.

Signed-off-by: Li RongQing <lirongqing@baidu.com>
Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>
Reviewed-by: Ankit Soni <Ankit.Soni@amd.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Stable-dep-of: 00a7dd64888d ("iommu/amd: Do not reallocate GA log buffers on resume")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/iommu/amd/init.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index 6bb9d3661baed..0561c17a24e73 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -854,10 +854,11 @@ static void __init free_command_buffer(struct amd_iommu *iommu)
 void *__init iommu_alloc_4k_pages(struct amd_iommu *iommu, gfp_t gfp,
 				  size_t size)
 {
+	int nid = iommu->dev ? dev_to_node(&iommu->dev->dev) : NUMA_NO_NODE;
 	void *buf;
 
 	size = PAGE_ALIGN(size);
-	buf = iommu_alloc_pages_sz(gfp, size);
+	buf = iommu_alloc_pages_node_sz(nid, gfp, size);
 	if (!buf)
 		return NULL;
 	if (check_feature(FEATURE_SNP) &&
@@ -972,14 +973,16 @@ static int iommu_ga_log_enable(struct amd_iommu *iommu)
 
 static int iommu_init_ga_log(struct amd_iommu *iommu)
 {
+	int nid = iommu->dev ? dev_to_node(&iommu->dev->dev) : NUMA_NO_NODE;
+
 	if (!AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir))
 		return 0;
 
-	iommu->ga_log = iommu_alloc_pages_sz(GFP_KERNEL, GA_LOG_SIZE);
+	iommu->ga_log = iommu_alloc_pages_node_sz(nid, GFP_KERNEL, GA_LOG_SIZE);
 	if (!iommu->ga_log)
 		goto err_out;
 
-	iommu->ga_log_tail = iommu_alloc_pages_sz(GFP_KERNEL, 8);
+	iommu->ga_log_tail = iommu_alloc_pages_node_sz(nid, GFP_KERNEL, 8);
 	if (!iommu->ga_log_tail)
 		goto err_out;
 
-- 
2.53.0