[PATCH v9 06/13] iommu/amd: copy old trans table from old kernel

Baoquan He
2017-08-01T11:37:56Z

Here several things need be done:
- If iommu is pre-enabled in a normal kernel, just disable it and print
warning.

- If any one of IOMMUs is not pre-enabled in kdump kernel, just continue
as it does in normal kernel.

- If failed to copy dev table of old kernel, continue to proceed as
it does in normal kernel.

- Only if all IOMMUs are pre-enabled and copy dev table is done well, free
the dev table allocated in early_amd_iommu_init() and make amd_iommu_dev_table
point to the copied one.

- Disable and Re-enable event/cmd buffer, install the copied DTE table
to reg, and detect and enable guest vapic.

- Flush all caches

Signed-off-by: Baoquan He <bhe@redhat.com>
---
drivers/iommu/amd_iommu_init.c | 57 ++++++++++++++++++++++++++++++++++++------
1 file changed, 50 insertions(+), 7 deletions(-)

diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index ab6794539527..e3d8af9d9636 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -37,6 +37,7 @@
#include <asm/io_apic.h>
#include <asm/irq_remapping.h>

+#include <linux/crash_dump.h>
#include "amd_iommu_proto.h"
#include "amd_iommu_types.h"
#include "irq_remapping.h"
@@ -1498,9 +1499,12 @@ static int __init init_iommu_one(struct amd_iommu *iommu, struct ivhd_header *h)
iommu->int_enabled = false;

init_translation_status(iommu);
-
- if (translation_pre_enabled(iommu))
- pr_warn("Translation is already enabled - trying to copy translation structures\n");
+ if (translation_pre_enabled(iommu) && !is_kdump_kernel()) {
+ iommu_disable(iommu);
+ clear_translation_pre_enabled(iommu);
+ pr_warn("Translation was enabled for IOMMU:%d but we are not in kdump mode\n",
+ iommu->index);
+ }

ret = init_iommu_from_acpi(iommu, h);
if (ret)
@@ -1995,8 +1999,7 @@ static int __init init_memory_definitions(struct acpi_table_header *table)
}

/*
- * Init the device table to not allow DMA access for devices and
- * suppress all page faults
+ * Init the device table to not allow DMA access for devices
*/
static void init_device_table_dma(void)
{
@@ -2137,9 +2140,49 @@ static void early_enable_iommu(struct amd_iommu *iommu)
static void early_enable_iommus(void)
{
struct amd_iommu *iommu;
+ bool is_pre_disabled = false;

- for_each_iommu(iommu)
- early_enable_iommu(iommu);
+ for_each_iommu(iommu) {
+ if (!translation_pre_enabled(iommu)) {
+ is_pre_disabled = true;
+ break;
+ }
+ }
+
+ if (is_pre_disabled) {
+ for_each_iommu(iommu)
+ early_enable_iommu(iommu);
+ } else {
+ pr_warn("Translation is already enabled - trying to copy translation structures\n");
+ if (copy_device_table()) {
+ pr_err("Failed to copy DEV table from previous kernel.\n");
+ /*
+ * If failed to copy dev tables from old kernel, continue to proceed
+ * as it does in normal kernel.
+ */
+ if(old_dev_tbl_cpy != NULL)
+ free_pages((unsigned long)old_dev_tbl_cpy,
+ get_order(dev_table_size));
+ for_each_iommu(iommu) {
+ clear_translation_pre_enabled(iommu);
+ early_enable_iommu(iommu);
+ }
+ } else {
+ pr_info("Copied DEV table from previous kernel.\n");
+ free_pages((unsigned long)amd_iommu_dev_table,
+ get_order(dev_table_size));
+ amd_iommu_dev_table = old_dev_tbl_cpy;
+ for_each_iommu(iommu) {
+ iommu_disable_command_buffer(iommu);
+ iommu_disable_event_buffer(iommu);
+ iommu_enable_command_buffer(iommu);
+ iommu_enable_event_buffer(iommu);
+ iommu_enable_ga(iommu);
+ iommu_set_device_table(iommu);
+ iommu_flush_all_caches(iommu);
+ }
+ }
+ }

#ifdef CONFIG_IRQ_REMAP
if (AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir))
--
2.5.5