--- /dev/null
+From 5ecef76682ef506bae706f8122f056fe723d9c7c Mon Sep 17 00:00:00 2001
+From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+Date: Fri, 9 Jan 2026 11:48:34 +0100
+Subject: Revert "iommu/amd: Skip enabling command/event buffers for kdump"
+
+From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+This reverts commit f33890f95140660923003ba1e2f114dee20e691b which is
+commit 9be15fbfc6c5c89c22cf6e209f66ea43ee0e58bb upstream.
+
+This causes problems in older kernel trees as SNP host kdump is not
+supported in them, so drop it from the stable branches.
+
+Reported-by: Ashish Kalra <ashish.kalra@amd.com>
+Link: https://lore.kernel.org/r/dacdff7f-0606-4ed5-b056-2de564404d51@amd.com
+Cc: Vasant Hegde <vasant.hegde@amd.com>
+Cc: Sairaj Kodilkar <sarunkod@amd.com>
+Cc: Joerg Roedel <joerg.roedel@amd.com>
+Cc: Sasha Levin <sashal@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/iommu/amd/init.c | 28 +++++++++-------------------
+ 1 file changed, 9 insertions(+), 19 deletions(-)
+
+--- a/drivers/iommu/amd/init.c
++++ b/drivers/iommu/amd/init.c
+@@ -805,16 +805,11 @@ static void iommu_enable_command_buffer(
+
+ BUG_ON(iommu->cmd_buf == NULL);
+
+- if (!is_kdump_kernel()) {
+- /*
+- * Command buffer is re-used for kdump kernel and setting
+- * of MMIO register is not required.
+- */
+- entry = iommu_virt_to_phys(iommu->cmd_buf);
+- entry |= MMIO_CMD_SIZE_512;
+- memcpy_toio(iommu->mmio_base + MMIO_CMD_BUF_OFFSET,
+- &entry, sizeof(entry));
+- }
++ entry = iommu_virt_to_phys(iommu->cmd_buf);
++ entry |= MMIO_CMD_SIZE_512;
++
++ memcpy_toio(iommu->mmio_base + MMIO_CMD_BUF_OFFSET,
++ &entry, sizeof(entry));
+
+ amd_iommu_reset_cmd_buffer(iommu);
+ }
+@@ -863,15 +858,10 @@ static void iommu_enable_event_buffer(st
+
+ BUG_ON(iommu->evt_buf == NULL);
+
+- if (!is_kdump_kernel()) {
+- /*
+- * Event buffer is re-used for kdump kernel and setting
+- * of MMIO register is not required.
+- */
+- entry = iommu_virt_to_phys(iommu->evt_buf) | EVT_LEN_MASK;
+- memcpy_toio(iommu->mmio_base + MMIO_EVT_BUF_OFFSET,
+- &entry, sizeof(entry));
+- }
++ entry = iommu_virt_to_phys(iommu->evt_buf) | EVT_LEN_MASK;
++
++ memcpy_toio(iommu->mmio_base + MMIO_EVT_BUF_OFFSET,
++ &entry, sizeof(entry));
+
+ /* set head and tail to zero manually */
+ writel(0x00, iommu->mmio_base + MMIO_EVT_HEAD_OFFSET);