system/qemu
system/qemu
1
0
Fork 0
mirror of https://gitlab.com/qemu-project/qemu synced 2024-11-05 20:35:44 +00:00
Code Issues Projects Releases Packages Wiki Activity

target: ppc: Use MSR_HVB bit to get the target endianness for memory dump

Browse source 
Currently on PPC64 qemu always dumps the guest memory in
Big Endian (BE) format even though the guest running in Little Endian
(LE) mode. So crash tool fails to load the dump as illustrated below:

Log :
$ virsh dump DOMAIN --memory-only dump.file

Domain 'DOMAIN' dumped to dump.file

$ crash vmlinux dump.file

<snip>
crash 8.0.2-1.el9

WARNING: endian mismatch:
          crash utility: little-endian
          dump.file: big-endian

WARNING: machine type mismatch:
          crash utility: PPC64
          dump.file: (unknown)

crash: dump.file: not a supported file format
<snip>

This happens because cpu_get_dump_info() passes cpu->env->has_hv_mode
to function ppc_interrupts_little_endian(), the cpu->env->has_hv_mode
always set for powerNV even though the guest is not running in hv mode.
The hv mode should be taken from msr_mask MSR_HVB bit
(cpu->env.msr_mask & MSR_HVB). This patch fixes the issue by passing
MSR_HVB value to ppc_interrupts_little_endian() in order to determine
the guest endianness.

The crash tool also expects guest kernel endianness should match the
endianness of the dump.

The patch was tested on POWER9 box booted with Linux as host in
following cases:

Host-Endianess Qemu-Target-Machine                Qemu-Generated-Guest
                                                  Memory-Dump-Format
BE             powernv(OPAL/PowerNV)                   LE
BE             powernv(OPAL/PowerNV)                   BE
LE             powernv(OPAL/PowerNV)                   LE
LE             powernv(OPAL/PowerNV)                   BE
LE             pseries(OPAL/PowerNV/pSeries) KVMHV     LE
LE             pseries TCG                             LE

Fixes: 5609400a42 ("target/ppc: Set the correct endianness for powernv memory
dumps")
Signed-off-by: Narayana Murty N <nnmlinux@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Message-ID: <20230623072506.34713-1-nnmlinux@linux.ibm.com>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
This commit is contained in:
Narayana Murty N 2023-06-23 03:25:06 -04:00 committed by Daniel Henrique Barboza
parent 4e6b7db2c3
commit 93c691a003
1 changed files with 1 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
target/ppc/arch_dump.c
View file

@ -237,7 +237,7 @@ int cpu_get_dump_info(ArchDumpInfo *info,
info->d_machine = PPC_ELF_MACHINE;
info->d_class = ELFCLASS;
if (ppc_interrupts_little_endian(cpu, cpu->env.has_hv_mode)) {
if (ppc_interrupts_little_endian(cpu, !!(cpu->env.msr_mask & MSR_HVB))) {
info->d_endian = ELFDATA2LSB;
} else {
info->d_endian = ELFDATA2MSB;