Revert "iommu/amd: Skip enabling command/event buffers for kdump"

This reverts commit 44a764aec64b3f3235b9cbac2525222f69685418 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>

diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index 977ec5c5aa45365f0713e537ba98ad321cf3f4c3..6261bc7304e97b44233f264b262dd452d69aead9 100644 (file)
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -840,16 +840,11 @@ 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);
 }
@@ -898,15 +893,10 @@ 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);