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

This reverts commit 3344716ddee01d7caa35b470d30fd87781c661b1 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 8659cb0bc7e6d31eef595bea69a502be23fcf59e..e1816ae8699dd19bd48ebb023ed0743b2d22043f 100644 (file)
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -816,16 +816,11 @@ 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);
 }
@@ -874,15 +869,10 @@ 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);