x86/hyperv: Set MTRR state when running as SEV-SNP Hyper-V guest

In order to avoid mappings using the UC- cache attribute, set the
MTRR state to use WB caching as the default.

This is needed in order to cope with the fact that PAT is enabled,
while MTRRs are not supported by the hypervisor.

Fixes: 90b926e68f ("x86/pat: Fix pat_x_mtrr_type() for MTRR disabled case")
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20230502120931.20719-5-jgross@suse.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
This commit is contained in:
Juergen Gross 2023-05-02 14:09:19 +02:00 committed by Borislav Petkov (AMD)
parent 29055dc742
commit c957f1f3c4
1 changed files with 4 additions and 0 deletions

View File

@ -17,6 +17,7 @@
#include <asm/mem_encrypt.h>
#include <asm/mshyperv.h>
#include <asm/hypervisor.h>
#include <asm/mtrr.h>
#ifdef CONFIG_AMD_MEM_ENCRYPT
@ -372,6 +373,9 @@ void __init hv_vtom_init(void)
x86_platform.guest.enc_cache_flush_required = hv_vtom_cache_flush_required;
x86_platform.guest.enc_tlb_flush_required = hv_vtom_tlb_flush_required;
x86_platform.guest.enc_status_change_finish = hv_vtom_set_host_visibility;
/* Set WB as the default cache mode. */
mtrr_overwrite_state(NULL, 0, MTRR_TYPE_WRBACK);
}
#endif /* CONFIG_AMD_MEM_ENCRYPT */