Il 17/07/2013 18:16, Dave Hansen ha scritto: > I'm causing qemu to spew these emulation failure messages until I kill > it. The guest kernel being run has been hacked up pretty heavily and is > probably either accessing bad physical addresses (above the address > ranges in the e820 table) or trying to DMA to bad addresses. > > What I'd really like qemu to be doing is trapping back in to the guest > kernel to have it handle this issue. Then I'd have a better chance of > dumping out some debugging information to see where I went wrong. This is happening because the kernel is executing a PCMPEQB instruction on an invalid memory address. This instruction is not yet emulated by KVM. If you want QEMU to trap back to the guest kernel, you can add emulation of the instruction to arch/x86/kvm/emulate.c. If you do not really care about the guest doing something sane, you can use a stub emulation function that is just "return emulate_ud(ctxt)". That alone could be a good starting point to attach a kernel debugger to the guest. Paolo > host kernel: 3.10 > guest kernel: Linus commit d2b4a64 + patches > qemu: v1.4.0-2835-g6453a3a > >> > KVM internal error. Suberror: 1 >> > emulation failure >> > RAX=0000000000000000 RBX=00000000013c0410 RCX=0000000000000010 RDX=0000000000000010 >> > RSI=000000000000000a RDI=00007f6d256a73c0 RBP=ffffffffffffffff RSP=00007fffe2720ce8 >> > R8 =00000000ffffffff R9 =0000000000000000 R10=0000000000000022 R11=0000000000000246 >> > R12=00007fffe2720d58 R13=0000000000000400 R14=00007f6d256a7000 R15=0000000000000000 >> > RIP=00007f6d24c5a50e RFL=00010202 [-------] CPL=3 II=0 A20=1 SMM=0 HLT=0 >> > ES =0000 0000000000000000 ffffffff 00c00000 >> > CS =0033 0000000000000000 ffffffff 00a0fb00 DPL=3 CS64 [-RA] >> > SS =002b 0000000000000000 ffffffff 00c0f300 DPL=3 DS [-WA] >> > DS =0000 0000000000000000 ffffffff 00c00000 >> > FS =0000 00007f6d2569d740 ffffffff 00c00000 >> > GS =0000 0000000000000000 ffffffff 00c00000 >> > LDT=0000 0000000000000000 ffffffff 00c00000 >> > TR =0040 ffff88007b190480 00002087 00008b00 DPL=0 TSS64-busy >> > GDT= ffff88007b184000 0000007f >> > IDT= ffffffffff57a000 00000fff >> > CR0=80050033 CR2=00007f6d256a7000 CR3=000000006f13b000 CR4=000006e0 >> > DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000 >> > DR6=00000000ffff0ff0 DR7=0000000000000400 >> > EFER=0000000000000d01 >> > Code=d7 c3 85 c0 0f 85 bc 00 00 00 48 83 ea 10 0f 8e d2 00 00 00 <66> 0f 74 4f 30 66 0f d7 c1 85 c0 0f 85 b1 00 00 00 48 31 c0 c3 66 66 66 66 2e 0f 1f 84 00 >> > KVM internal error. Suberror: 1 >> > emulation failure >> > RAX=0000000000000000 RBX=00000000013c0410 RCX=0000000000000010 RDX=0000000000000010 >> > RSI=000000000000000a RDI=00007f6d256a73c0 RBP=ffffffffffffffff RSP=00007fffe2720ce8 >> > R8 =00000000ffffffff R9 =0000000000000000 R10=0000000000000022 R11=0000000000000246 >> > R12=00007fffe2720d58 R13=0000000000000400 R14=00007f6d256a7000 R15=0000000000000000 >> > RIP=00007f6d24c5a50e RFL=00010202 [-------] CPL=3 II=0 A20=1 SMM=0 HLT=0 >> > ES =0000 0000000000000000 ffffffff 00c00000 >> > CS =0033 0000000000000000 ffffffff 00a0fb00 DPL=3 CS64 [-RA] >> > SS =002b 0000000000000000 ffffffff 00c0f300 DPL=3 DS [-WA] >> > DS =0000 0000000000000000 ffffffff 00c00000 >> > FS =0000 00007f6d2569d740 ffffffff 00c00000 >> > GS =0000 0000000000000000 ffffffff 00c00000 >> > LDT=0000 0000000000000000 ffffffff 00c00000 >> > TR =0040 ffff88007b190480 00002087 00008b00 DPL=0 TSS64-busy >> > GDT= ffff88007b184000 0000007f >> > IDT= ffffffffff57a000 00000fff >> > CR0=80050033 CR2=00007f6d256a7000 CR3=000000006f13b000 CR4=000006e0 >> > DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000 >> > DR6=00000000ffff0ff0 DR7=0000000000000400 >> > EFER=0000000000000d01 >> > Code=d7 c3 85 c0 0f 85 bc 00 00 00 48 83 ea 10 0f 8e d2 00 00 00 <66> 0f 74 4f 30 66 0f d7 c1 85 c0 0f 85 b1 00 00 00 48 31 c0 c3 66 66 66 66 2e 0f 1f 84 00 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
