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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2024-10-15 12:58:17 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2024-10-20 07:07:02 -0400
commit8e690b817e38769dc2fa0e7473e5a5dc1fc25795 (patch)
treebbe51d126b176306c2f51dba5520354cea20a058 /arch/x86
parentbc07eea2f3b330127242df2e0ec2d6cd16b4f2e8 (diff)
x86/kvm: Override default caching mode for SEV-SNP and TDX
AMD SEV-SNP and Intel TDX have limited access to MTRR: either it is not advertised in CPUID or it cannot be programmed (on TDX, due to #VE on CR0.CD clear). This results in guests using uncached mappings where it shouldn't and pmd/pud_set_huge() failures due to non-uniform memory type reported by mtrr_type_lookup(). Override MTRR state, making it WB by default as the kernel does for Hyper-V guests. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Suggested-by: Binbin Wu <binbin.wu@intel.com> Cc: Juergen Gross <jgross@suse.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Reviewed-by: Juergen Gross <jgross@suse.com> Message-ID: <20241015095818.357915-1-kirill.shutemov@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kernel/kvm.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 263f8aed4e2c..21e9e4845354 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -37,6 +37,7 @@
#include <asm/apic.h>
#include <asm/apicdef.h>
#include <asm/hypervisor.h>
+#include <asm/mtrr.h>
#include <asm/tlb.h>
#include <asm/cpuidle_haltpoll.h>
#include <asm/ptrace.h>
@@ -980,6 +981,9 @@ static void __init kvm_init_platform(void)
}
kvmclock_init();
x86_platform.apic_post_init = kvm_apic_init;
+
+ /* Set WB as the default cache mode for SEV-SNP and TDX */
+ mtrr_overwrite_state(NULL, 0, MTRR_TYPE_WRBACK);
}
#if defined(CONFIG_AMD_MEM_ENCRYPT)