Re: [PATCH v8 06/13] iommu/amd: copy old trans table from old kernel

[Baoquan He]

On 07/27/17 at 05:38pm, Joerg Roedel wrote:
> On Fri, Jul 21, 2017 at 04:59:04PM +0800, Baoquan He wrote:
> > @@ -2128,9 +2131,43 @@ static void early_enable_iommu(struct amd_iommu 
> > *iommu)
> >  static void early_enable_iommus(void)
> >  {
> > struct amd_iommu *iommu;
> > +   bool is_pre_enabled = false;
> >  
> > -   for_each_iommu(iommu)
> > -   early_enable_iommu(iommu);
> > +   for_each_iommu(iommu) {
> > +   if (translation_pre_enabled(iommu)) {
> > +   is_pre_enabled = true;
> > +   break;
> > +   }
> > +   }
> 
> is_pre_enabled should only be true when _all_ iommus are pre-enabled. If
> only one is found disabled just disable the others and continue without
> copying the device table.

OK, will change as you suggested.

> 
___
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

Re: [PATCH v8 06/13] iommu/amd: copy old trans table from old kernel

[Joerg Roedel]

On Fri, Jul 21, 2017 at 04:59:04PM +0800, Baoquan He wrote:
> @@ -2128,9 +2131,43 @@ static void early_enable_iommu(struct amd_iommu *iommu)
>  static void early_enable_iommus(void)
>  {
>   struct amd_iommu *iommu;
> + bool is_pre_enabled = false;
>  
> - for_each_iommu(iommu)
> - early_enable_iommu(iommu);
> + for_each_iommu(iommu) {
> + if (translation_pre_enabled(iommu)) {
> + is_pre_enabled = true;
> + break;
> + }
> + }

is_pre_enabled should only be true when _all_ iommus are pre-enabled. If
only one is found disabled just disable the others and continue without
copying the device table.

___
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

[PATCH v8 06/13] iommu/amd: copy old trans table from old kernel

[Baoquan He]

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

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

- 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 
---
 drivers/iommu/amd_iommu_init.c | 51 --
 1 file changed, 44 insertions(+), 7 deletions(-)

diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index c58f091ce232..aa9b5918d11f 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -37,6 +37,7 @@
 #include 
 #include 
 
+#include 
 #include "amd_iommu_proto.h"
 #include "amd_iommu_types.h"
 #include "irq_remapping.h"
@@ -1489,9 +1490,12 @@ 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)
@@ -1986,8 +1990,7 @@ 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)
 {
@@ -2128,9 +2131,43 @@ static void early_enable_iommu(struct amd_iommu *iommu)
 static void early_enable_iommus(void)
 {
struct amd_iommu *iommu;
+   bool is_pre_enabled = false;
 
-   for_each_iommu(iommu)
-   early_enable_iommu(iommu);
+   for_each_iommu(iommu) {
+   if (translation_pre_enabled(iommu)) {
+   is_pre_enabled = true;
+   break;
+   }
+   }
+
+   if (!is_pre_enabled) {
+   for_each_iommu(iommu)
+   early_enable_iommu(iommu);
+   } else {
+   pr_warn("Translation is already enabled - trying to copy 
translation structures\n");
+   if (copy_dev_tables()) {
+   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.
+*/
+   for_each_iommu(iommu) {
+   clear_translation_pre_enabled(iommu);
+   early_enable_iommu(iommu);
+   }
+   } else {
+   pr_info("Copied DEV table from previous kernel.\n");
+   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

___
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu