From 6d39bdee238f9799718653a9d4d61ebf2922e23d Mon Sep 17 00:00:00 2001 From: Suravee Suthikulpanit Date: Thu, 5 Nov 2020 14:58:32 +0000 Subject: [PATCH] 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: c69d89aff393 ("iommu/amd: Use 4K page for completion wait write-back semaphore") Signed-off-by: Suravee Suthikulpanit Cc: Brijesh Singh Link: https://lore.kernel.org/r/20201105145832.3065-1-suravee.suthikulpanit@amd.com Signed-off-by: Will Deacon --- drivers/iommu/amd/init.c | 27 ++++++++++++++++++++++----- 1 file changed, 22 insertions(+), 5 deletions(-) diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c index 82e4af8f09bbb..23a790f8f5506 100644 --- a/drivers/iommu/amd/init.c +++ b/drivers/iommu/amd/init.c @@ -29,6 +29,7 @@ #include #include #include +#include #include @@ -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; } -- 2.39.5