Re: [PATCH] tools/xl: add suspend-to-ram and resume subcommands

[zithro <slack@xxxxxxxxx>]

Added my S-o-B (no other change).

On 29 Feb 2024 08:00, zithro / Cyril Rébert wrote:
> The xl command doesn't provide suspend/resume, so add them :
>    xl suspend-to-ram <Domain>
>    xl resume <Domain>
>
> This patch follows a discussion on XenDevel: when you want the
> virtualized equivalent of "sleep"-ing a host, it's better to
> suspend/resume than to pause/unpause a domain.
>
> Suggested-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Suggested-by: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Cyril Rébert (zithro) <slack@xxxxxxxxx>
> ---
> - Tested on v4.17, x86
> - the function "libxl_domain_resume" is called like libvirt does, so
>    using a "co-operative resume", but I don't know what it means (:
> - there may be a problem with the words resume <-> restore, like
>    for "LIBXL_HAVE_NO_SUSPEND_RESUME"
> - for the docs, I only slightly adapted a copy/paste from xl pause ...
> ---
> ---
>   docs/man/xl.1.pod.in    | 10 ++++++++++
>   tools/xl/xl.h           |  2 ++
>   tools/xl/xl_cmdtable.c  | 10 ++++++++++
>   tools/xl/xl_vmcontrol.c | 36 ++++++++++++++++++++++++++++++++++++
>   4 files changed, 58 insertions(+)
>
> diff --git a/docs/man/xl.1.pod.in b/docs/man/xl.1.pod.in
> index bed8393473..63d80f1449 100644
> --- a/docs/man/xl.1.pod.in
> +++ b/docs/man/xl.1.pod.in
> @@ -682,6 +682,10 @@ Pass the VNC password to vncviewer via stdin.
>   
>   =back
>   
> +=item B<resume> I<domain-id>
> +
> +Resume a domain, after having been suspended to RAM.
> +
>   =item B<save> [I<OPTIONS>] I<domain-id> I<checkpointfile> [I<configfile>]
>   
>   Saves a running domain to a state file so that it can be restored
> @@ -760,6 +764,12 @@ in response to this event.
>   
>   =back
>   
> +=item B<suspend-to-ram> I<domain-id>
> +
> +Suspend a domain to RAM.  When in a suspended state the domain will still
> +consume allocated resources (such as memory), but will not be eligible for
> +scheduling by the Xen hypervisor. It is in a shutdown state, but not dying.
> +
>   =item B<sysrq> I<domain-id> I<letter>
>   
>   Send a <Magic System Request> to the domain, each type of request is
> diff --git a/tools/xl/xl.h b/tools/xl/xl.h
> index 9c86bb1d98..716ad32423 100644
> --- a/tools/xl/xl.h
> +++ b/tools/xl/xl.h
> @@ -133,6 +133,8 @@ int main_migrate(int argc, char **argv);
>   int main_dump_core(int argc, char **argv);
>   int main_pause(int argc, char **argv);
>   int main_unpause(int argc, char **argv);
> +int main_suspendtoram(int argc, char **argv);
> +int main_resume(int argc, char **argv);
>   int main_destroy(int argc, char **argv);
>   int main_shutdown(int argc, char **argv);
>   int main_reboot(int argc, char **argv);
> diff --git a/tools/xl/xl_cmdtable.c b/tools/xl/xl_cmdtable.c
> index 62bdb2aeaa..1382282252 100644
> --- a/tools/xl/xl_cmdtable.c
> +++ b/tools/xl/xl_cmdtable.c
> @@ -136,6 +136,16 @@ const struct cmd_spec cmd_table[] = {
>         "Unpause a paused domain",
>         "<Domain>",
>       },
> +    { "suspend-to-ram",
> +      &main_suspendtoram, 0, 1,
> +      "Suspend a domain to RAM",
> +      "<Domain>",
> +    },
> +    { "resume",
> +      &main_resume, 0, 1,
> +      "Resume a domain from RAM",
> +      "<Domain>",
> +    },
>       { "console",
>         &main_console, 0, 0,
>         "Attach to domain's console",
> diff --git a/tools/xl/xl_vmcontrol.c b/tools/xl/xl_vmcontrol.c
> index 98f6bd2e76..ba45f89c5a 100644
> --- a/tools/xl/xl_vmcontrol.c
> +++ b/tools/xl/xl_vmcontrol.c
> @@ -42,6 +42,16 @@ static void unpause_domain(uint32_t domid)
>       libxl_domain_unpause(ctx, domid, NULL);
>   }
>   
> +static void suspend_domain_toram(uint32_t domid)
> +{
> +    libxl_domain_suspend_only(ctx, domid, NULL);
> +}
> +
> +static void resume_domain(uint32_t domid)
> +{
> +    libxl_domain_resume(ctx, domid, 1, NULL);
> +}
> +
>   static void destroy_domain(uint32_t domid, int force)
>   {
>       int rc;
> @@ -82,6 +92,32 @@ int main_unpause(int argc, char **argv)
>       return EXIT_SUCCESS;
>   }
>   
> +int main_suspendtoram(int argc, char **argv)
> +{
> +    int opt;
> +
> +    SWITCH_FOREACH_OPT(opt, "", NULL, "suspend-to-ram", 1) {
> +        /* No options */
> +    }
> +
> +    suspend_domain_toram(find_domain(argv[optind]));
> +
> +    return EXIT_SUCCESS;
> +}
> +
> +int main_resume(int argc, char **argv)
> +{
> +    int opt;
> +
> +    SWITCH_FOREACH_OPT(opt, "", NULL, "resume", 1) {
> +        /* No options */
> +    }
> +
> +    resume_domain(find_domain(argv[optind]));
> +
> +    return EXIT_SUCCESS;
> +}
> +
>   int main_destroy(int argc, char **argv)
>   {
>       int opt;
--
++
zithro / Cyril