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

This reverts commit bb8f9de71c9bd442ec5e1d52ce830428860892f0 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 9549fbffa66d0800da13aa5ebdfee00cb9ae967c..065d626d590505d2c27e05ee0e74e11b076500e2 100644 (file)
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -696,16 +696,11 @@ 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);
 }
@@ -754,15 +749,10 @@ 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);