diff options
| author | Lev Kujawski <lkujaw@member.fsf.org> | 2022-05-21 08:15:11 +0000 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-05-25 05:23:40 -0400 |
| commit | 0471a7bd1bca2a47a5f378f2222c5cf39ce94152 (patch) | |
| tree | e35c69319f81b3fd234697bc267df09707c6a535 /arch/x86/kvm/x86.c | |
| parent | cc07e60b0811eeeca769fb342aa6e13da5977657 (diff) | |
| download | linux-0471a7bd1bca2a47a5f378f2222c5cf39ce94152.tar.gz | |
KVM: set_msr_mce: Permit guests to ignore single-bit ECC errors
Certain guest operating systems (e.g., UNIXWARE) clear bit 0 of
MC1_CTL to ignore single-bit ECC data errors. Single-bit ECC data
errors are always correctable and thus are safe to ignore because they
are informational in nature rather than signaling a loss of data
integrity.
Prior to this patch, these guests would crash upon writing MC1_CTL,
with resultant error messages like the following:
error: kvm run failed Operation not permitted
EAX=fffffffe EBX=fffffffe ECX=00000404 EDX=ffffffff
ESI=ffffffff EDI=00000001 EBP=fffdaba4 ESP=fffdab20
EIP=c01333a5 EFL=00000246 [---Z-P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0108 00000000 ffffffff 00c09300 DPL=0 DS [-WA]
CS =0100 00000000 ffffffff 00c09b00 DPL=0 CS32 [-RA]
SS =0108 00000000 ffffffff 00c09300 DPL=0 DS [-WA]
DS =0108 00000000 ffffffff 00c09300 DPL=0 DS [-WA]
FS =0000 00000000 ffffffff 00c00000
GS =0000 00000000 ffffffff 00c00000
LDT=0118 c1026390 00000047 00008200 DPL=0 LDT
TR =0110 ffff5af0 00000067 00008b00 DPL=0 TSS32-busy
GDT= ffff5020 000002cf
IDT= ffff52f0 000007ff
CR0=8001003b CR2=00000000 CR3=0100a000 CR4=00000230
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000
DR6=ffff0ff0 DR7=00000400
EFER=0000000000000000
Code=08 89 01 89 51 04 c3 8b 4c 24 08 8b 01 8b 51 04 8b 4c 24 04 <0f>
30 c3 f7 05 a4 6d ff ff 10 00 00 00 74 03 0f 31 c3 33 c0 33 d2 c3 8d
74 26 00 0f 31 c3
Signed-off-by: Lev Kujawski <lkujaw@member.fsf.org>
Message-Id: <20220521081511.187388-1-lkujaw@member.fsf.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index b81ef4f497f4..b5aeed18b9f5 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3234,10 +3234,13 @@ static int set_msr_mce(struct kvm_vcpu *vcpu, struct msr_data *msr_info) /* only 0 or all 1s can be written to IA32_MCi_CTL * some Linux kernels though clear bit 10 in bank 4 to * workaround a BIOS/GART TBL issue on AMD K8s, ignore - * this to avoid an uncatched #GP in the guest + * this to avoid an uncatched #GP in the guest. + * + * UNIXWARE clears bit 0 of MC1_CTL to ignore + * correctable, single-bit ECC data errors. */ if ((offset & 0x3) == 0 && - data != 0 && (data | (1 << 10)) != ~(u64)0) + data != 0 && (data | (1 << 10) | 1) != ~(u64)0) return -1; /* MCi_STATUS */ |