From 816b2eac151a9bcce4eff7119207e088ad45236f Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Fri, 9 Jan 2026 11:48:34 +0100 Subject: [PATCH] Revert "iommu/amd: Skip enabling command/event buffers for kdump" This reverts commit 30e91eeb0bc9b3daf402b26176d1d52c29ab53e4 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 Link: https://lore.kernel.org/r/dacdff7f-0606-4ed5-b056-2de564404d51@amd.com Cc: Vasant Hegde Cc: Sairaj Kodilkar Cc: Joerg Roedel Cc: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/iommu/amd/init.c | 28 +++++++++------------------- 1 file changed, 9 insertions(+), 19 deletions(-) diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c index 8ac0ac915efd3..1ba6adb5b9124 100644 --- a/drivers/iommu/amd/init.c +++ b/drivers/iommu/amd/init.c @@ -697,16 +697,11 @@ static void iommu_enable_command_buffer(struct amd_iommu *iommu) 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); } @@ -755,15 +750,10 @@ static void iommu_enable_event_buffer(struct amd_iommu *iommu) 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); -- 2.47.3