Commit 6d39bdee authored by Suravee Suthikulpanit's avatar Suravee Suthikulpanit Committed by Will Deacon
Browse files

iommu/amd: Enforce 4k mapping for certain IOMMU data structures 



AMD IOMMU requires 4k-aligned pages for the event log, the PPR log,
and the completion wait write-back regions. However, when allocating
the pages, they could be part of large mapping (e.g. 2M) page.
This causes #PF due to the SNP RMP hardware enforces the check based
on the page level for these data structures.

So, fix by calling set_memory_4k() on the allocated pages.

Fixes: c69d89af ("iommu/amd: Use 4K page for completion wait write-back semaphore")
Signed-off-by: default avatarSuravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Link: https://lore.kernel.org/r/20201105145832.3065-1-suravee.suthikulpanit@amd.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 91c2c28d

drivers/iommu/amd/init.c

+22 −5
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include <asm/iommu_table.h>

#include <asm/io_apic.h>

#include <asm/irq_remapping.h>

#include <asm/set_memory.h>



#include <linux/crash_dump.h>
@@ -672,11 +673,27 @@ static void __init free_command_buffer(struct amd_iommu *iommu) 
	free_pages((unsigned long)iommu->cmd_buf, get_order(CMD_BUFFER_SIZE));

}



static void *__init iommu_alloc_4k_pages(struct amd_iommu *iommu,

					 gfp_t gfp, size_t size)

{

	int order = get_order(size);

	void *buf = (void *)__get_free_pages(gfp, order);



	if (buf &&

	    iommu_feature(iommu, FEATURE_SNP) &&

	    set_memory_4k((unsigned long)buf, (1 << order))) {

		free_pages((unsigned long)buf, order);

		buf = NULL;

	}



	return buf;

}



/* allocates the memory where the IOMMU will log its events to */

static int __init alloc_event_buffer(struct amd_iommu *iommu)

{

	iommu->evt_buf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,

						  get_order(EVT_BUFFER_SIZE));

	iommu->evt_buf = iommu_alloc_4k_pages(iommu, GFP_KERNEL | __GFP_ZERO,

					      EVT_BUFFER_SIZE);



	return iommu->evt_buf ? 0 : -ENOMEM;

}
@@ -715,8 +732,8 @@ static void __init free_event_buffer(struct amd_iommu *iommu) 
/* allocates the memory where the IOMMU will log its events to */

static int __init alloc_ppr_log(struct amd_iommu *iommu)

{

	iommu->ppr_log = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,

						  get_order(PPR_LOG_SIZE));

	iommu->ppr_log = iommu_alloc_4k_pages(iommu, GFP_KERNEL | __GFP_ZERO,

					      PPR_LOG_SIZE);



	return iommu->ppr_log ? 0 : -ENOMEM;

}
@@ -838,7 +855,7 @@ static int iommu_init_ga(struct amd_iommu *iommu) 


static int __init alloc_cwwb_sem(struct amd_iommu *iommu)

{

	iommu->cmd_sem = (void *)get_zeroed_page(GFP_KERNEL);

	iommu->cmd_sem = iommu_alloc_4k_pages(iommu, GFP_KERNEL | __GFP_ZERO, 1);



	return iommu->cmd_sem ? 0 : -ENOMEM;

}

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