On 2024-02-29 02:00, 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.coop...@citrix.com>
Suggested-by: Marek Marczykowski-Górecki <marma...@invisiblethingslab.com>

You should include you S-o-B here to certify your patch under the Developer's Certificate of Origin. You can read what that means in CONTRIBUTING. tl;dr: You are stating you can make the open source contribution.

I tested this with a PVH and HVM guest. suspend-to-ram and resume seem to function properly. The VCPUs stop, but the domain & qemu remain. Resume works - the VCPUs start running again.

However, the domain destruction seems to hang on poweroff. The VM transitions to powered off - state shutdown - but the domain and QEMU instance are not cleaned up.

If I power off without a suspend-to-ram, everything is cleaned up properly.

Have you seen this? It's not your code, but I guess something with libxl or qemu.

---
- 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 ...
---

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);
+}
+

I would just inline these functions below.

  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)

Maybe main_suspend_to_ram to be closer to the command line suspend-to-ram.

Thanks,
Jason

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