From c957f1f3c498bcce85c04e92e60afbae1fd10cde Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Tue, 2 May 2023 14:09:19 +0200 Subject: 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: 90b926e68f50 ("x86/pat: Fix pat_x_mtrr_type() for MTRR disabled case") Signed-off-by: Juergen Gross Signed-off-by: Borislav Petkov (AMD) Tested-by: Michael Kelley Link: https://lore.kernel.org/r/20230502120931.20719-5-jgross@suse.com Signed-off-by: Borislav Petkov (AMD) --- arch/x86/hyperv/ivm.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/x86/hyperv/ivm.c') diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c index cc92388b7a99..6f7c1b5606ad 100644 --- a/arch/x86/hyperv/ivm.c +++ b/arch/x86/hyperv/ivm.c @@ -17,6 +17,7 @@ #include #include #include +#include #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 */ -- cgit v1.2.3