libvirt/libxl-set-cach-mode.patch

From 9b37c98cf768eb02afb384522a72ec36850876bf Mon Sep 17 00:00:00 2001
From: Jim Fehlig <jfehlig@suse.com>
Date: Tue, 5 Jul 2022 11:27:47 -0600
Subject: libxl: Allow setting disk cache mode

https://bugzilla.novell.com/show_bug.cgi?id=879425

Signed-off-by: Jim Fehlig <jfehlig@suse.com>
---
 src/libxl/libxl_conf.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

Index: libvirt-8.7.0/src/libxl/libxl_conf.c
===================================================================
--- libvirt-8.7.0.orig/src/libxl/libxl_conf.c
+++ libvirt-8.7.0/src/libxl/libxl_conf.c
@@ -941,6 +941,28 @@ libxlDiskSetDiscard(libxl_device_disk *x
     }
 }
 
+static void
+libxlDiskSetCacheMode(libxl_device_disk *x_disk, int cachemode)
+{
+    switch (cachemode) {
+#if defined(LIBXL_HAVE_LIBXL_DEVICE_DISK_DISABLE_FLUSH_MAGIC)
+    case VIR_DOMAIN_DISK_CACHE_UNSAFE:
+        if (x_disk->readwrite)
+            x_disk->readwrite = (x_disk->readwrite & LIBXL_HAVE_LIBXL_DEVICE_DISK_DISABLE_FLUSH_MASK) | LIBXL_HAVE_LIBXL_DEVICE_DISK_DISABLE_FLUSH_MAGIC;
+        break;
+#endif
+    case VIR_DOMAIN_DISK_CACHE_DIRECTSYNC:
+        x_disk->direct_io_safe = true;
+        break;
+    case VIR_DOMAIN_DISK_CACHE_DEFAULT:
+    case VIR_DOMAIN_DISK_CACHE_DISABLE:
+    case VIR_DOMAIN_DISK_CACHE_WRITETHRU:
+    case VIR_DOMAIN_DISK_CACHE_WRITEBACK:
+    default:
+        break;
+    }
+}
+
 static char *
 libxlMakeNetworkDiskSrcStr(virStorageSource *src,
                            const char *username,
@@ -1180,6 +1202,7 @@ libxlMakeDisk(virDomainDiskDef *l_disk,
     x_disk->readwrite = !l_disk->src->readonly;
     x_disk->is_cdrom = l_disk->device == VIR_DOMAIN_DISK_DEVICE_CDROM ? 1 : 0;
     libxlDiskSetDiscard(x_disk, l_disk->discard);
+    libxlDiskSetCacheMode(x_disk, l_disk->cachemode);
     /* An empty CDROM must have the empty format, otherwise libxl fails. */
     if (x_disk->is_cdrom && !x_disk->pdev_path)
         x_disk->format = LIBXL_DISK_FORMAT_EMPTY;