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x86/ioremap: Map EFI runtime services data as encrypted for SEV

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The dmidecode program fails to properly decode the SMBIOS data supplied
by OVMF/UEFI when running in an SEV guest. The SMBIOS area, under SEV, is
encrypted and resides in reserved memory that is marked as EFI runtime
services data.

As a result, when memremap() is attempted for the SMBIOS data, it
can't be mapped as regular RAM (through try_ram_remap()) and, since
the address isn't part of the iomem resources list, it isn't mapped
encrypted through the fallback ioremap().

Add a new __ioremap_check_other() to deal with memory types like
EFI_RUNTIME_SERVICES_DATA which are not covered by the resource ranges.

This allows any runtime services data which has been created encrypted,
to be mapped encrypted too.

 [ bp: Move functionality to a separate function. ]

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Joerg Roedel <jroedel@suse.de>
Tested-by: Joerg Roedel <jroedel@suse.de>
Cc: <stable@vger.kernel.org> # 5.3
Link: https://lkml.kernel.org/r/2d9e16eb5b53dc82665c95c6764b7407719df7a0.1582645327.git.thomas.lendacky@amd.com
This commit is contained in:
Tom Lendacky 2020-03-10 18:35:57 +01:00 committed by Borislav Petkov
parent 2c523b344d
commit 985e537a40
1 changed files with 18 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

18
arch/x86/mm/ioremap.c
View file

@ -106,6 +106,19 @@ static unsigned int __ioremap_check_encrypted(struct resource *res)
return 0;
}
/*
* The EFI runtime services data area is not covered by walk_mem_res(), but must
* be mapped encrypted when SEV is active.
*/
static void __ioremap_check_other(resource_size_t addr, struct ioremap_desc *desc)
{
if (!sev_active())
return;
if (efi_mem_type(addr) == EFI_RUNTIME_SERVICES_DATA)
desc->flags |= IORES_MAP_ENCRYPTED;
}
static int __ioremap_collect_map_flags(struct resource *res, void *arg)
{
struct ioremap_desc *desc = arg;
@ -124,6 +137,9 @@ static int __ioremap_collect_map_flags(struct resource *res, void *arg)
* To avoid multiple resource walks, this function walks resources marked as
* IORESOURCE_MEM and IORESOURCE_BUSY and looking for system RAM and/or a
* resource described not as IORES_DESC_NONE (e.g. IORES_DESC_ACPI_TABLES).
*
* After that, deal with misc other ranges in __ioremap_check_other() which do
* not fall into the above category.
*/
static void __ioremap_check_mem(resource_size_t addr, unsigned long size,
struct ioremap_desc *desc)
@ -135,6 +151,8 @@ static void __ioremap_check_mem(resource_size_t addr, unsigned long size,
memset(desc, 0, sizeof(struct ioremap_desc));
walk_mem_res(start, end, desc, __ioremap_collect_map_flags);
__ioremap_check_other(addr, desc);
}
/*