From 93c691a003193a8bc4db54f4e544e19d6b1016fc Mon Sep 17 00:00:00 2001 From: Narayana Murty N Date: Fri, 23 Jun 2023 03:25:06 -0400 Subject: [PATCH] target: ppc: Use MSR_HVB bit to get the target endianness for memory dump 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 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 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: 5609400a4228 ("target/ppc: Set the correct endianness for powernv memory dumps") Signed-off-by: Narayana Murty N Reviewed-by: Nicholas Piggin Reviewed-by: Greg Kurz Reviewed-by: Vaibhav Jain Message-ID: <20230623072506.34713-1-nnmlinux@linux.ibm.com> Signed-off-by: Daniel Henrique Barboza --- target/ppc/arch_dump.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/target/ppc/arch_dump.c b/target/ppc/arch_dump.c index f58e6359d5..a8315659d9 100644 --- a/target/ppc/arch_dump.c +++ b/target/ppc/arch_dump.c @@ -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;