* Re: [PATCH v4] target: ppc: Use MSR_HVB bit to get the target endianness for memory dump
2023-06-23 7:25 [PATCH v4] target: ppc: Use MSR_HVB bit to get the target endianness for memory dump Narayana Murty N
@ 2023-07-01 10:26 ` Nicholas Piggin
2023-07-03 9:35 ` Greg Kurz
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Nicholas Piggin @ 2023-07-01 10:26 UTC (permalink / raw)
To: Narayana Murty N, danielhb413, clg, david, groug
Cc: qemu-ppc, qemu-devel, farosas, npiggin, vaibhav, harshpb, sbhat
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;
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH v4] target: ppc: Use MSR_HVB bit to get the target endianness for memory dump
2023-06-23 7:25 [PATCH v4] target: ppc: Use MSR_HVB bit to get the target endianness for memory dump Narayana Murty N
2023-07-01 10:26 ` Nicholas Piggin
@ 2023-07-03 9:35 ` Greg Kurz
2023-07-03 13:50 ` Daniel Henrique Barboza
2023-07-04 7:48 ` Vaibhav Jain
3 siblings, 0 replies; 5+ messages in thread
From: Greg Kurz @ 2023-07-03 9:35 UTC (permalink / raw)
To: Narayana Murty N
Cc: danielhb413, clg, david, npiggin, qemu-ppc, qemu-devel, farosas,
npiggin, vaibhav, harshpb, sbhat
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;
--
Greg
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH v4] target: ppc: Use MSR_HVB bit to get the target endianness for memory dump
2023-06-23 7:25 [PATCH v4] target: ppc: Use MSR_HVB bit to get the target endianness for memory dump Narayana Murty N
2023-07-01 10:26 ` Nicholas Piggin
2023-07-03 9:35 ` Greg Kurz
@ 2023-07-03 13:50 ` Daniel Henrique Barboza
2023-07-04 7:48 ` Vaibhav Jain
3 siblings, 0 replies; 5+ messages in thread
From: Daniel Henrique Barboza @ 2023-07-03 13:50 UTC (permalink / raw)
To: Narayana Murty N, clg, david, groug, npiggin
Cc: qemu-ppc, qemu-devel, farosas, npiggin, vaibhav, harshpb, sbhat
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;
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH v4] target: ppc: Use MSR_HVB bit to get the target endianness for memory dump
2023-06-23 7:25 [PATCH v4] target: ppc: Use MSR_HVB bit to get the target endianness for memory dump Narayana Murty N
` (2 preceding siblings ...)
2023-07-03 13:50 ` Daniel Henrique Barboza
@ 2023-07-04 7:48 ` Vaibhav Jain
3 siblings, 0 replies; 5+ messages in thread
From: Vaibhav Jain @ 2023-07-04 7:48 UTC (permalink / raw)
To: Narayana Murty N, danielhb413, clg, david, groug, npiggin
Cc: qemu-ppc, qemu-devel, farosas, npiggin, harshpb, sbhat, nnmlinux
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>
--
Cheers
~ Vaibhav
^ permalink raw reply [flat|nested] 5+ messages in thread