Messages in this thread Patch in this message | | | Date | Tue, 3 Nov 2020 14:35:50 +0100 | From | Joerg Roedel <> | Subject | Re: [PATCH] iommu/amd: Enforce 4k mapping for certain IOMMU data structures |
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Hi Suravee,
On Wed, Oct 28, 2020 at 11:18:24PM +0000, Suravee Suthikulpanit wrote: > 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: commit c69d89aff393 ("iommu/amd: Use 4K page for completion wait write-back semaphore") > Cc: Brijesh Singh <brijesh.singh@amd.com> > Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> > --- > drivers/iommu/amd/init.c | 22 +++++++++++++++++----- > 1 file changed, 17 insertions(+), 5 deletions(-) > > diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c > index 82e4af8f09bb..75dc30226a7c 100644 > --- a/drivers/iommu/amd/init.c > +++ b/drivers/iommu/amd/init.c > @@ -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 +673,22 @@ 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(gfp_t gfp, size_t size) > +{ > + void *buf; > + int order = get_order(size); > + > + buf = (void *)__get_free_pages(gfp, order); > + if (!buf) > + return buf; > + return set_memory_4k((unsigned long)buf, (1 << order)) ? NULL : buf; > +} > +
Please make the 4k split only if SNP is actually enabled in the system.
Regards,
Joerg
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