Message ID | 20230623072506.34713-1-nnmlinux@linux.ibm.com |
---|---|
State | New |
Headers | show |
Series | [v4] target: ppc: Use MSR_HVB bit to get the target endianness for memory dump | expand |
On Fri Jun 23, 2023 at 5:25 PM AEST, Narayana Murty N wrote: > 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: 5609400a4228 ("target/ppc: Set the correct endianness for powernv memory > dumps") > Signed-off-by: Narayana Murty N <nnmlinux@linux.ibm.com> Did I forget to send RB? It looks good to me now, thanks for clearing up my confusion. Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Thanks, Nick > --- > Changes since V3: > commit message modified as per feedback from Greg Kurz, Cédric Le > Goater and Nicholas Piggin. > Changes since V2: > commit message modified as per feedback from Nicholas Piggin. > Changes since V1: > https://lore.kernel.org/qemu-devel/20230420145055.10196-1-nnmlinux@linux.ibm.com/ > The approach to solve the issue was changed based on feedback from > Fabiano Rosas on patch V1. > --- > 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;
On Fri, 23 Jun 2023 03:25:06 -0400 Narayana Murty N <nnmlinux@linux.ibm.com> wrote: > 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: 5609400a4228 ("target/ppc: Set the correct endianness for powernv memory > dumps") > Signed-off-by: Narayana Murty N <nnmlinux@linux.ibm.com> > --- Thanks ! Reviewed-by: Greg Kurz <groug@kaod.org> > Changes since V3: > commit message modified as per feedback from Greg Kurz, Cédric Le > Goater and Nicholas Piggin. > Changes since V2: > commit message modified as per feedback from Nicholas Piggin. > Changes since V1: > https://lore.kernel.org/qemu-devel/20230420145055.10196-1-nnmlinux@linux.ibm.com/ > The approach to solve the issue was changed based on feedback from > Fabiano Rosas on patch V1. > --- > 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;
Queued in gitlab.com/danielhb/qemu/tree/ppc-next. Thanks, Daniel On 6/23/23 04:25, Narayana Murty N wrote: > 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: 5609400a4228 ("target/ppc: Set the correct endianness for powernv memory > dumps") > Signed-off-by: Narayana Murty N <nnmlinux@linux.ibm.com> > --- > Changes since V3: > commit message modified as per feedback from Greg Kurz, Cédric Le > Goater and Nicholas Piggin. > Changes since V2: > commit message modified as per feedback from Nicholas Piggin. > Changes since V1: > https://lore.kernel.org/qemu-devel/20230420145055.10196-1-nnmlinux@linux.ibm.com/ > The approach to solve the issue was changed based on feedback from > Fabiano Rosas on patch V1. > --- > 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;
Thanks for fixing this Narayana, Narayana Murty N <nnmlinux@linux.ibm.com> writes: > 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: 5609400a4228 ("target/ppc: Set the correct endianness for powernv memory > dumps") > Signed-off-by: Narayana Murty N <nnmlinux@linux.ibm.com> Reviewed-by: Vaibhav Jain<vaibhav@linux.ibm.com>
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;
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: 5609400a4228 ("target/ppc: Set the correct endianness for powernv memory dumps") Signed-off-by: Narayana Murty N <nnmlinux@linux.ibm.com> --- Changes since V3: commit message modified as per feedback from Greg Kurz, Cédric Le Goater and Nicholas Piggin. Changes since V2: commit message modified as per feedback from Nicholas Piggin. Changes since V1: https://lore.kernel.org/qemu-devel/20230420145055.10196-1-nnmlinux@linux.ibm.com/ The approach to solve the issue was changed based on feedback from Fabiano Rosas on patch V1. --- target/ppc/arch_dump.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)