Hello
I am testing my own x86_64 kernel with QEMU/KVM and it report cryptic
error "KVM internal error. Suberror: 1". I believe this emulation
error happens in Linux kernel most likely in arch/x86/kvm/emulate.c
I tested KVM with Linux 4.4.0, 4.12.3 and both versions return this
emulation error. It is strange as QEMU emulation and VMWare work fine
with the same kernel binary.
How to understand what is the KVM issue and why it fails? Is there a
way to obtain more information about the error?
Here is my code where the issue happens:
0000000000100c20 <console_write>:
100c20: 48 85 f6 test %rsi,%rsi
100c23: 0f 84 11 05 00 00 je 10113a <console_write+0x51a>
100c29: 45 31 c0 xor %r8d,%r8d
100c2c: b9 0e 8f 0b 00 mov $0xb8f0e,%ecx
100c31: 66 66 66 66 66 66 2e data32 data32 data32 data32
data32 nopw %cs:0x0(%rax,%rax,1)
100c38: 0f 1f 84 00 00 00 00
100c3f: 00
100c40: 0f be 07 movsbl (%rdi),%eax
100c43: 0f b7 d0 movzwl %ax,%edx
100c46: 83 fa 0a cmp $0xa,%edx
100c49: 0f 85 91 00 00 00 jne 100ce0 <console_write+0xc0>
100c4f: 48 8b 05 aa 83 00 00 mov 0x83aa(%rip),%rax
# 109000 <row>
100c56: 48 8d 50 01 lea 0x1(%rax),%rdx
100c5a: 48 89 15 9f 83 00 00 mov %rdx,0x839f(%rip)
# 109000 <row>
100c61: 48 83 fa 19 cmp $0x19,%rdx
100c65: 0f 85 35 04 00 00 jne 1010a0 <console_write+0x480>
100c6b: 31 d2 xor %edx,%edx
100c6d: 0f 1f 00 nopl (%rax)
100c70: 0f 10 84 51 92 f1 ff movups -0xe6e(%rcx,%rdx,2),%xmm0
^^^^^^^^^^^^ KVM error happens here ^^^^^^^ See registers stack below
100c77: ff
100c78: 0f 11 84 51 f2 f0 ff movups %xmm0,-0xf0e(%rcx,%rdx,2)
100c7f: ff
100c80: 48 83 c2 08 add $0x8,%rdx
100c84: 48 81 fa 80 07 00 00 cmp $0x780,%rdx
100c8b: 75 e3 jne 100c70 <console_write+0x50>
100c8d: 48 89 05 6c 83 00 00 mov %rax,0x836c(%rip)
# 109000 <row>
100c94: 48 c7 05 c1 3b 00 00 movq $0xb8f00,0x3bc1(%rip)
# 104860 <cursor>
100c9b: 00 8f 0b 00
100c9f: 4c 8b 0d 62 83 00 00 mov 0x8362(%rip),%r9
# 109008 <column>
100ca6: 4d 85 c9 test %r9,%r9
100ca9: 0f 84 71 04 00 00 je 101120 <console_write+0x500>
100caf: 49 8d 41 ff lea -0x1(%r9),%rax
100cb3: 44 89 ca mov %r9d,%edx
100cb6: 83 e2 07 and $0x7,%edx
100cb9: 48 83 f8 07 cmp $0x7,%rax
100cbd: 0f 83 f6 03 00 00 jae 1010b9 <console_write+0x499>
Registers at KVM error as reported by QEMU
RAX=0000000000000018 RBX=0000000000000001 RCX=00000000000b8f0e
RDX=0000000000000000
RSI=0000000000000001 RDI=000000000010445a RBP=000000000010445b
RSP=000000000010af78
R8 =0000000000000000 R9 =00000000000b8f56 R10=000000000010445c
R11=0000000000000004
R12=000000000010445a R13=000000007fffffd3 R14=0000000000000001
R15=000000000000002c
RIP=0000000000100c70 RFL=00010246 [---Z-P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0000 0000000000000000 ffffffff 00c00000
CS =0008 0000000000000000 00000000 00209900 DPL=0 CS64 [--A]
SS =0000 0000000000000000 ffffffff 00c00000
DS =0000 0000000000000000 ffffffff 00c00000
FS =0000 0000000000000000 ffffffff 00c00000
GS =0000 0000000000000000 ffffffff 00c00000
LDT=0000 0000000000000000 0000ffff 00008200 DPL=0 LDT
TR =0000 0000000000000000 0000ffff 00008b00 DPL=0 TSS64-busy
GDT= 0000000000104518 0000000f
IDT= 0000000000105030 00000fff
CR0=80000033 CR2=0000000000000000 CR3=0000000000107000 CR4=00000620
DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000
DR3=0000000000000000
DR6=00000000ffff0ff0 DR7=0000000000000400
EFER=0000000000000500
