Re: [PATCH v4 5/5] kexec: document -s, -c and -a options.
On Fri, 16 Mar 2018 14:51:14 +0800 Dave Young wrote: > On 03/15/18 at 12:44pm, Michal Suchánek wrote: > > On Wed, 14 Mar 2018 15:50:31 +0800 > > Dave Young wrote: > > > > > On 03/14/18 at 08:25am, Michal Suchánek wrote: > > > > On Wed, 14 Mar 2018 11:41:30 +0800 > > > > Dave Young wrote: > > > > > > > > > On 03/06/18 at 02:15pm, Michal Suchanek wrote: > > > > > > Signed-off-by: Michal Suchanek > > > > > > --- > > > > > > kexec/kexec.8 | 15 +++ > > > > > > 1 file changed, 15 insertions(+) > > > > > > > > > > > > diff --git a/kexec/kexec.8 b/kexec/kexec.8 > > > > > > index e0131b4ea827..b3543db3f413 100644 > > > > > > --- a/kexec/kexec.8 > > > > > > +++ b/kexec/kexec.8 > > > > > > @@ -144,6 +144,21 @@ Load the new kernel for use on panic. > > > > > > Specify that the new kernel is of this > > > > > > .I type. > > > > > > .TP > > > > > > +.BI \-s\ (\-\-kexec-file-syscall) > > > > > > +Specify that the new KEXEC_FILE_LOAD syscall should be used > > > > > > exclusively. > > > > > > > > > > Maybe better to be simple like below: > > > > > "Use kexec_file_load syscall to load the new kernel." > > > > > > > > > > > > > > > > +.TP > > > > > > +.BI \-c\ (\-\-kexec-syscall) > > > > > > +Specify that the old KEXEC_LOAD syscall should be used > > > > > > exclusively (the default). > > > > > > > > > > similarly: > > > > > "Use kexec_load syscall to load the new kernel." > > > > > > > > > > > +.TP > > > > > > +.BI \-a\ (\-\-kexec-syscall-auto) > > > > > > +Try the new simpler KEXEC_FILE_LOAD syscall first and if > > > > > > it is not supported +fall back to the old KEXEC_LOAD > > > > > > interface. + > > > > > > +There is no one single interface that always works. > > > > > > KEXEC_FILE_LOAD is required +on systems that use locked-down > > > > > > secure boot to verify the kernel signature. +KEXEC_LOAD is > > > > > > required for some kernel image formats and on architectures > > > > > > that +do not support KEXEC_FILE_LOAD. > > > > > > > > > > It seems not good to say kexec_file_load is simpler and newer. > > > > > Also it is not a must for Secure Boot and locked down kernel > > > > > only. So it would be better to just simplify and use the first > > > > > paragraph: > > > > > > > > > > "Try kexec_file_load syscall first and if it is not supported > > > > > fall back to the kexec_load syscall" > > > > > > > > There was a request for explanation so just the first paragraph > > > > will not do. What is it required for other than secure boot? > > > > > > People can use kexec -s to load a signed kernel but not necessary > > > to boot with Secure Boot enabled. > > > > Is booting signed kernel without -s not supported? If so I would > > consider it kexec-tools bug. And it should documented then as well I > > guess. > > I'm not sure I understand the question. In kernel we splitted kexec > and kexec_file they can be enabled as kernel config options > separately. If one want to a secured kexec (not UEFI Secure Boot, > only signed kernel loading) then one can only enable > CONFIG_KEXEC_FILE but disable CONFIG_KEXEC. In this case without > '-s' load will fail. But if one enabled both CONFIG_KEXEC_FILE and > CONFIG_KEXEC then kexec load without '-s' still works. This is currently not supported by kexec-tools. Status does not use KEXEC_FILE Thanks Michal ___ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
Re: [PATCH v4 5/5] kexec: document -s, -c and -a options.
On 03/15/18 at 12:44pm, Michal Suchánek wrote: > On Wed, 14 Mar 2018 15:50:31 +0800 > Dave Young wrote: > > > On 03/14/18 at 08:25am, Michal Suchánek wrote: > > > On Wed, 14 Mar 2018 11:41:30 +0800 > > > Dave Young wrote: > > > > > > > On 03/06/18 at 02:15pm, Michal Suchanek wrote: > > > > > Signed-off-by: Michal Suchanek > > > > > --- > > > > > kexec/kexec.8 | 15 +++ > > > > > 1 file changed, 15 insertions(+) > > > > > > > > > > diff --git a/kexec/kexec.8 b/kexec/kexec.8 > > > > > index e0131b4ea827..b3543db3f413 100644 > > > > > --- a/kexec/kexec.8 > > > > > +++ b/kexec/kexec.8 > > > > > @@ -144,6 +144,21 @@ Load the new kernel for use on panic. > > > > > Specify that the new kernel is of this > > > > > .I type. > > > > > .TP > > > > > +.BI \-s\ (\-\-kexec-file-syscall) > > > > > +Specify that the new KEXEC_FILE_LOAD syscall should be used > > > > > exclusively. > > > > > > > > Maybe better to be simple like below: > > > > "Use kexec_file_load syscall to load the new kernel." > > > > > > > > > > > > > +.TP > > > > > +.BI \-c\ (\-\-kexec-syscall) > > > > > +Specify that the old KEXEC_LOAD syscall should be used > > > > > exclusively (the default). > > > > > > > > similarly: > > > > "Use kexec_load syscall to load the new kernel." > > > > > > > > > +.TP > > > > > +.BI \-a\ (\-\-kexec-syscall-auto) > > > > > +Try the new simpler KEXEC_FILE_LOAD syscall first and if it is > > > > > not supported +fall back to the old KEXEC_LOAD interface. > > > > > + > > > > > +There is no one single interface that always works. > > > > > KEXEC_FILE_LOAD is required +on systems that use locked-down > > > > > secure boot to verify the kernel signature. +KEXEC_LOAD is > > > > > required for some kernel image formats and on architectures > > > > > that +do not support KEXEC_FILE_LOAD. > > > > > > > > It seems not good to say kexec_file_load is simpler and newer. > > > > Also it is not a must for Secure Boot and locked down kernel > > > > only. So it would be better to just simplify and use the first > > > > paragraph: > > > > > > > > "Try kexec_file_load syscall first and if it is not supported fall > > > > back to the kexec_load syscall" > > > > > > There was a request for explanation so just the first paragraph will > > > not do. What is it required for other than secure boot? > > > > People can use kexec -s to load a signed kernel but not necessary to > > boot with Secure Boot enabled. > > Is booting signed kernel without -s not supported? If so I would > consider it kexec-tools bug. And it should documented then as well I > guess. I'm not sure I understand the question. In kernel we splitted kexec and kexec_file they can be enabled as kernel config options separately. If one want to a secured kexec (not UEFI Secure Boot, only signed kernel loading) then one can only enable CONFIG_KEXEC_FILE but disable CONFIG_KEXEC. In this case without '-s' load will fail. But if one enabled both CONFIG_KEXEC_FILE and CONFIG_KEXEC then kexec load without '-s' still works. > > > > > There is no Secure Boot in powerpc, arm64 now. > > Is there not yet? Anyway, the intent is to support it which is probably > the reason we have the syscall in the first place. Secure Boot is UEFI only, AFAIK powerpc does not have UEFI, arm64 has UEFI but I do not see Secure Boot. Also powerpc version kexec_file_load does not have signature verification. > > Thanks > > Michal Thanks Dave ___ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
Re: [PATCH v4 5/5] kexec: document -s, -c and -a options.
On Wed, 14 Mar 2018 15:50:31 +0800 Dave Young wrote: > On 03/14/18 at 08:25am, Michal Suchánek wrote: > > On Wed, 14 Mar 2018 11:41:30 +0800 > > Dave Young wrote: > > > > > On 03/06/18 at 02:15pm, Michal Suchanek wrote: > > > > Signed-off-by: Michal Suchanek > > > > --- > > > > kexec/kexec.8 | 15 +++ > > > > 1 file changed, 15 insertions(+) > > > > > > > > diff --git a/kexec/kexec.8 b/kexec/kexec.8 > > > > index e0131b4ea827..b3543db3f413 100644 > > > > --- a/kexec/kexec.8 > > > > +++ b/kexec/kexec.8 > > > > @@ -144,6 +144,21 @@ Load the new kernel for use on panic. > > > > Specify that the new kernel is of this > > > > .I type. > > > > .TP > > > > +.BI \-s\ (\-\-kexec-file-syscall) > > > > +Specify that the new KEXEC_FILE_LOAD syscall should be used > > > > exclusively. > > > > > > Maybe better to be simple like below: > > > "Use kexec_file_load syscall to load the new kernel." > > > > > > > > > > +.TP > > > > +.BI \-c\ (\-\-kexec-syscall) > > > > +Specify that the old KEXEC_LOAD syscall should be used > > > > exclusively (the default). > > > > > > similarly: > > > "Use kexec_load syscall to load the new kernel." > > > > > > > +.TP > > > > +.BI \-a\ (\-\-kexec-syscall-auto) > > > > +Try the new simpler KEXEC_FILE_LOAD syscall first and if it is > > > > not supported +fall back to the old KEXEC_LOAD interface. > > > > + > > > > +There is no one single interface that always works. > > > > KEXEC_FILE_LOAD is required +on systems that use locked-down > > > > secure boot to verify the kernel signature. +KEXEC_LOAD is > > > > required for some kernel image formats and on architectures > > > > that +do not support KEXEC_FILE_LOAD. > > > > > > It seems not good to say kexec_file_load is simpler and newer. > > > Also it is not a must for Secure Boot and locked down kernel > > > only. So it would be better to just simplify and use the first > > > paragraph: > > > > > > "Try kexec_file_load syscall first and if it is not supported fall > > > back to the kexec_load syscall" > > > > There was a request for explanation so just the first paragraph will > > not do. What is it required for other than secure boot? > > People can use kexec -s to load a signed kernel but not necessary to > boot with Secure Boot enabled. Is booting signed kernel without -s not supported? If so I would consider it kexec-tools bug. And it should documented then as well I guess. > > There is no Secure Boot in powerpc, arm64 now. Is there not yet? Anyway, the intent is to support it which is probably the reason we have the syscall in the first place. Thanks Michal ___ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
Re: [PATCH v4 5/5] kexec: document -s, -c and -a options.
On Wed, 14 Mar 2018 11:43:55 +0800 Dave Young wrote: > On 03/06/18 at 02:15pm, Michal Suchanek wrote: > > Signed-off-by: Michal Suchanek > > --- > > kexec/kexec.8 | 15 +++ > > 1 file changed, 15 insertions(+) > > > > diff --git a/kexec/kexec.8 b/kexec/kexec.8 > > index e0131b4ea827..b3543db3f413 100644 > > --- a/kexec/kexec.8 > > +++ b/kexec/kexec.8 > > @@ -144,6 +144,21 @@ Load the new kernel for use on panic. > > Specify that the new kernel is of this > > .I type. > > .TP > > +.BI \-s\ (\-\-kexec-file-syscall) > > +Specify that the new KEXEC_FILE_LOAD syscall should be used > > exclusively. +.TP > > +.BI \-c\ (\-\-kexec-syscall) > > +Specify that the old KEXEC_LOAD syscall should be used exclusively > > (the default). +.TP > > +.BI \-a\ (\-\-kexec-syscall-auto) > > +Try the new simpler KEXEC_FILE_LOAD syscall first and if it is not > > supported +fall back to the old KEXEC_LOAD interface. > > + > > +There is no one single interface that always works. > > KEXEC_FILE_LOAD is required +on systems that use locked-down secure > > boot to verify the kernel signature. +KEXEC_LOAD is required for > > some kernel image formats and on architectures that +do not support > > KEXEC_FILE_LOAD. +.TP > > .B \-u\ (\-\-unload) > > Unload the current > > .B kexec > > -- > > 2.13.6 > > > > Actually while I replied this mail, I tried 'kexec -c -a' system > immediately rebooted. Also as I noted in patch 4 a 'break' is missing > so does it work on your side? Right, the original single-patch code had a bug which is now fixed but new one crept in. Since we still don't agree how it *should* behave it is too early to say it deviates from expectation. If we agree what it should do but it turns out to be broken it can be fixed after the fact, too. Thanks Michal ___ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
Re: [PATCH v4 5/5] kexec: document -s, -c and -a options.
On 03/14/18 at 08:25am, Michal Suchánek wrote: > On Wed, 14 Mar 2018 11:41:30 +0800 > Dave Young wrote: > > > On 03/06/18 at 02:15pm, Michal Suchanek wrote: > > > Signed-off-by: Michal Suchanek > > > --- > > > kexec/kexec.8 | 15 +++ > > > 1 file changed, 15 insertions(+) > > > > > > diff --git a/kexec/kexec.8 b/kexec/kexec.8 > > > index e0131b4ea827..b3543db3f413 100644 > > > --- a/kexec/kexec.8 > > > +++ b/kexec/kexec.8 > > > @@ -144,6 +144,21 @@ Load the new kernel for use on panic. > > > Specify that the new kernel is of this > > > .I type. > > > .TP > > > +.BI \-s\ (\-\-kexec-file-syscall) > > > +Specify that the new KEXEC_FILE_LOAD syscall should be used > > > exclusively. > > > > Maybe better to be simple like below: > > "Use kexec_file_load syscall to load the new kernel." > > > > > > > +.TP > > > +.BI \-c\ (\-\-kexec-syscall) > > > +Specify that the old KEXEC_LOAD syscall should be used exclusively > > > (the default). > > > > similarly: > > "Use kexec_load syscall to load the new kernel." > > > > > +.TP > > > +.BI \-a\ (\-\-kexec-syscall-auto) > > > +Try the new simpler KEXEC_FILE_LOAD syscall first and if it is not > > > supported +fall back to the old KEXEC_LOAD interface. > > > + > > > +There is no one single interface that always works. > > > KEXEC_FILE_LOAD is required +on systems that use locked-down secure > > > boot to verify the kernel signature. +KEXEC_LOAD is required for > > > some kernel image formats and on architectures that +do not support > > > KEXEC_FILE_LOAD. > > > > It seems not good to say kexec_file_load is simpler and newer. Also > > it is not a must for Secure Boot and locked down kernel only. So it > > would be better to just simplify and use the first paragraph: > > > > "Try kexec_file_load syscall first and if it is not supported fall > > back to the kexec_load syscall" > > There was a request for explanation so just the first paragraph will > not do. What is it required for other than secure boot? People can use kexec -s to load a signed kernel but not necessary to boot with Secure Boot enabled. There is no Secure Boot in powerpc, arm64 now. > > Thanks > > Michal ___ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
Re: [PATCH v4 5/5] kexec: document -s, -c and -a options.
On Wed, 14 Mar 2018 11:41:30 +0800 Dave Young wrote: > On 03/06/18 at 02:15pm, Michal Suchanek wrote: > > Signed-off-by: Michal Suchanek > > --- > > kexec/kexec.8 | 15 +++ > > 1 file changed, 15 insertions(+) > > > > diff --git a/kexec/kexec.8 b/kexec/kexec.8 > > index e0131b4ea827..b3543db3f413 100644 > > --- a/kexec/kexec.8 > > +++ b/kexec/kexec.8 > > @@ -144,6 +144,21 @@ Load the new kernel for use on panic. > > Specify that the new kernel is of this > > .I type. > > .TP > > +.BI \-s\ (\-\-kexec-file-syscall) > > +Specify that the new KEXEC_FILE_LOAD syscall should be used > > exclusively. > > Maybe better to be simple like below: > "Use kexec_file_load syscall to load the new kernel." > > > > +.TP > > +.BI \-c\ (\-\-kexec-syscall) > > +Specify that the old KEXEC_LOAD syscall should be used exclusively > > (the default). > > similarly: > "Use kexec_load syscall to load the new kernel." > > > +.TP > > +.BI \-a\ (\-\-kexec-syscall-auto) > > +Try the new simpler KEXEC_FILE_LOAD syscall first and if it is not > > supported +fall back to the old KEXEC_LOAD interface. > > + > > +There is no one single interface that always works. > > KEXEC_FILE_LOAD is required +on systems that use locked-down secure > > boot to verify the kernel signature. +KEXEC_LOAD is required for > > some kernel image formats and on architectures that +do not support > > KEXEC_FILE_LOAD. > > It seems not good to say kexec_file_load is simpler and newer. Also > it is not a must for Secure Boot and locked down kernel only. So it > would be better to just simplify and use the first paragraph: > > "Try kexec_file_load syscall first and if it is not supported fall > back to the kexec_load syscall" There was a request for explanation so just the first paragraph will not do. What is it required for other than secure boot? Thanks Michal ___ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
Re: [PATCH v4 5/5] kexec: document -s, -c and -a options.
On 03/06/18 at 02:15pm, Michal Suchanek wrote: > Signed-off-by: Michal Suchanek > --- > kexec/kexec.8 | 15 +++ > 1 file changed, 15 insertions(+) > > diff --git a/kexec/kexec.8 b/kexec/kexec.8 > index e0131b4ea827..b3543db3f413 100644 > --- a/kexec/kexec.8 > +++ b/kexec/kexec.8 > @@ -144,6 +144,21 @@ Load the new kernel for use on panic. > Specify that the new kernel is of this > .I type. > .TP > +.BI \-s\ (\-\-kexec-file-syscall) > +Specify that the new KEXEC_FILE_LOAD syscall should be used exclusively. > +.TP > +.BI \-c\ (\-\-kexec-syscall) > +Specify that the old KEXEC_LOAD syscall should be used exclusively (the > default). > +.TP > +.BI \-a\ (\-\-kexec-syscall-auto) > +Try the new simpler KEXEC_FILE_LOAD syscall first and if it is not supported > +fall back to the old KEXEC_LOAD interface. > + > +There is no one single interface that always works. KEXEC_FILE_LOAD is > required > +on systems that use locked-down secure boot to verify the kernel signature. > +KEXEC_LOAD is required for some kernel image formats and on architectures > that > +do not support KEXEC_FILE_LOAD. > +.TP > .B \-u\ (\-\-unload) > Unload the current > .B kexec > -- > 2.13.6 > Actually while I replied this mail, I tried 'kexec -c -a' system immediately rebooted. Also as I noted in patch 4 a 'break' is missing so does it work on your side? I think it need more testing. Another question I have is not sure if '-c' is a good option letter, but I do not have suggestion as well.. Thanks Dave ___ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
Re: [PATCH v4 5/5] kexec: document -s, -c and -a options.
On 03/06/18 at 02:15pm, Michal Suchanek wrote: > Signed-off-by: Michal Suchanek > --- > kexec/kexec.8 | 15 +++ > 1 file changed, 15 insertions(+) > > diff --git a/kexec/kexec.8 b/kexec/kexec.8 > index e0131b4ea827..b3543db3f413 100644 > --- a/kexec/kexec.8 > +++ b/kexec/kexec.8 > @@ -144,6 +144,21 @@ Load the new kernel for use on panic. > Specify that the new kernel is of this > .I type. > .TP > +.BI \-s\ (\-\-kexec-file-syscall) > +Specify that the new KEXEC_FILE_LOAD syscall should be used exclusively. Maybe better to be simple like below: "Use kexec_file_load syscall to load the new kernel." > +.TP > +.BI \-c\ (\-\-kexec-syscall) > +Specify that the old KEXEC_LOAD syscall should be used exclusively (the > default). similarly: "Use kexec_load syscall to load the new kernel." > +.TP > +.BI \-a\ (\-\-kexec-syscall-auto) > +Try the new simpler KEXEC_FILE_LOAD syscall first and if it is not supported > +fall back to the old KEXEC_LOAD interface. > + > +There is no one single interface that always works. KEXEC_FILE_LOAD is > required > +on systems that use locked-down secure boot to verify the kernel signature. > +KEXEC_LOAD is required for some kernel image formats and on architectures > that > +do not support KEXEC_FILE_LOAD. It seems not good to say kexec_file_load is simpler and newer. Also it is not a must for Secure Boot and locked down kernel only. So it would be better to just simplify and use the first paragraph: "Try kexec_file_load syscall first and if it is not supported fall back to the kexec_load syscall" > +.TP > .B \-u\ (\-\-unload) > Unload the current > .B kexec > -- > 2.13.6 > ___ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
