Date: Sun, 29 Nov 2020 19:44:30 +0000 From: bugzilla-noreply@freebsd.org To: virtualization@FreeBSD.org Subject: [Bug 251464] OpenBSD 6.7 GPT bootloader causes unemulated instruction in low memory environment Message-ID: <bug-251464-27103@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D251464 Bug ID: 251464 Summary: OpenBSD 6.7 GPT bootloader causes unemulated instruction in low memory environment Product: Base System Version: 12.2-RELEASE Hardware: Any OS: Any Status: New Severity: Affects Only Me Priority: --- Component: bhyve Assignee: virtualization@FreeBSD.org Reporter: crowston@protonmail.com I am not able to boot a single-processor OpenBSD install with less than 300= MB of memory. Such a configuration kills bhyve with an unemulated instruction abort trap. For example: Failed to emulate instruction [0x45 0xf3 0x11 0xa3 0x3b 0x31 0xcf 0x18 0x48 0x74 0xcc 0x11 0xc4 0xb8 0x39] at 0xe9b656b ./start.sh: line 14: 98904 Abort trap bhyve -c sockets=3D1,cores=3D1,threads=3D1 -m 256M -H -w -u -s 0,amd_hostbridge -s 1:0,virtio-blk,/dev/zvol/tank0/bhyve/xxxx -s 1:1,virtio-net,tap3 -s 1:2,virtio-rnd -s 31,lpc -l bootrom,/usr/local/share/uefi-firmware/BHYVE_UEFI.fd -l com1,/dev/nmdm3A xx= xx Console output from the guest is probing: pc0 com0 com1 mem[640K 233M 16M 20K 4M 64K] disk: hd0 >> OpenBSD/amd64 BOOTX64 3.50 switching console to com0 >> OpenBSD/amd64 BOOTX64 3.50 boot>=20 booting hd0a:/bsd: 12879176+2753552+326368+0+704512 [811997- In the instruction hex is decoded in long mode, it looks like 0: 45 rex.RB 1: f3 11 a3 3b 31 cf 18 repz adc DWORD PTR [rbx+0x18cf313b],esp 8: 48 74 cc rex.W je 0xffffffffffffffd7 b: 11 c4 adc esp,eax d: b8 .byte 0xb8 e: 39 .byte 0x39 Booting the exact same configuration with 300 MB or 512 MB works correctly. I am running some patches on top of 12.2-RELEASE, so it's possible I broke something at some stage. I looked at vmm_instruction_emul.c, but none of the latest patches look like they add anything to do with rex.RB or repz adc. --=20 You are receiving this mail because: You are the assignee for the bug.=
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