Messages in this thread Patch in this message | | | From | Juergen Gross <> | Subject | [PATCH v4 04/12] x86/hyperv: set MTRR state when running as SEV-SNP Hyper-V guest | Date | Mon, 6 Mar 2023 17:34:17 +0100 |
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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 <jgross@suse.com> --- V2: - new patch --- arch/x86/kernel/cpu/mshyperv.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index f36dc2f796c5..0a6cc3cf8919 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -34,6 +34,7 @@ #include <clocksource/hyperv_timer.h> #include <asm/numa.h> #include <asm/coco.h> +#include <asm/mtrr.h> /* Is Linux running as the root partition? */ bool hv_root_partition; @@ -408,6 +409,9 @@ static void __init ms_hyperv_init_platform(void) #ifdef CONFIG_SWIOTLB swiotlb_unencrypted_base = ms_hyperv.shared_gpa_boundary; #endif + + /* Set WB as the default cache mode. */ + mtrr_overwrite_state(NULL, 0, MTRR_TYPE_WRBACK); } /* Isolation VMs are unenlightened SEV-based VMs, thus this check: */ if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) { -- 2.35.3
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