Mailing List Archive

commit 3c7482b73c5aa38e7faecccd649c67093001d3b5
Author: Jason Andryuk <jandryuk@gmail.com>
AuthorDate: Sun Apr 7 10:32:08 2024 -0400
Commit: Andrew Cooper <andrew.cooper3@citrix.com>
CommitDate: Thu Apr 11 16:39:10 2024 +0100

libxl: Use vkb=[] for HVMs

xl/libxl only applies vkb=[] to PV & PVH guests. HVM gets only a single
vkb by default, but that can be disabled by the vkb_device boolean.
Notably the HVM vkb cannot be configured, so feature-abs-pointer or the
backend-type cannot be specified.

Re-arrange the logic so that vkb=[] is handled regardless of domain
type. If vkb is empty or unspecified, follow the vkb_device boolean for
HVMs. Nothing changes for PVH & PV. HVMs can now get a configured vkb
instead of just the default one.

The chance for regression is an HVM config with
vkb=["$something"]
vkb_device=false

Which would now get a vkb.

This is useful for vGlass which provides a VKB to HVMs. vGlass wants to
specify feature-abs-pointer, but that is racily written by vGlass
instead of coming through the xl.cfg. Unhelpfully, Linux xen-kbdfront
reads the backend nodes without checking that the backend is in
InitWait.

Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Signed-off-by: Jason Andryuk <jason.andryuk@amd.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
---
CHANGELOG.md | 1 +
docs/man/xl.cfg.5.pod.in | 2 ++
tools/libs/light/libxl_create.c | 27 +++++++++++++++------------
3 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 93fda73c00..8041cfb7d2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
- On x86:
- HVM PIRQs are disabled by default.
- Reduce IOMMU setup time for hardware domain.
+ - xl/libxl configures vkb=[] for HVM domains with priority over vkb_device.

### Added
- On x86:
diff --git a/docs/man/xl.cfg.5.pod.in b/docs/man/xl.cfg.5.pod.in
index 039e057318..8f2b375ce9 100644
--- a/docs/man/xl.cfg.5.pod.in
+++ b/docs/man/xl.cfg.5.pod.in
@@ -2710,6 +2710,8 @@ device.

Specifies that the HVM guest gets a vkdb. The default is true (1).

+This option is only used when B<vkb=[]> is unset.
+
=item B<usb=BOOLEAN>

Enables or disables an emulated USB bus in the guest.
diff --git a/tools/libs/light/libxl_create.c b/tools/libs/light/libxl_create.c
index 5546335973..41252ec553 100644
--- a/tools/libs/light/libxl_create.c
+++ b/tools/libs/light/libxl_create.c
@@ -1769,24 +1769,32 @@ static void domcreate_launch_dm(libxl__egc *egc, libxl__multidev *multidev,
libxl__device_add(gc, domid, &libxl__virtio_devtype,
&d_config->virtios[i]);

+ if (d_config->num_vkbs) {
+ for (i = 0; i < d_config->num_vkbs; i++) {
+ ret = libxl__device_add(gc, domid, &libxl__vkb_devtype,
+ &d_config->vkbs[i]);
+ if (ret) goto error_out;
+ }
+ } else if (d_config->c_info.type == LIBXL_DOMAIN_TYPE_HVM &&
+ libxl_defbool_val(d_config->b_info.u.hvm.vkb_device)) {
+ libxl_device_vkb vkb;
+
+ libxl_device_vkb_init(&vkb);
+ libxl__device_add(gc, domid, &libxl__vkb_devtype, &vkb);
+ libxl_device_vkb_dispose(&vkb);
+ }
+
switch (d_config->c_info.type) {
case LIBXL_DOMAIN_TYPE_HVM:
{
libxl__device_console console;
libxl__device device;
- libxl_device_vkb vkb;

init_console_info(gc, &console, 0);
console.backend_domid = state->console_domid;
libxl__device_console_add(gc, domid, &console, state, &device);
libxl__device_console_dispose(&console);

- if (libxl_defbool_val(d_config->b_info.u.hvm.vkb_device)) {
- libxl_device_vkb_init(&vkb);
- libxl__device_add(gc, domid, &libxl__vkb_devtype, &vkb);
- libxl_device_vkb_dispose(&vkb);
- }
-
dcs->sdss.dm.guest_domid = domid;
if (libxl_defbool_val(d_config->b_info.device_model_stubdomain))
libxl__spawn_stub_dm(egc, &dcs->sdss);
@@ -1814,11 +1822,6 @@ static void domcreate_launch_dm(libxl__egc *egc, libxl__multidev *multidev,
&d_config->vfbs[i]);
}

- for (i = 0; i < d_config->num_vkbs; i++) {
- libxl__device_add(gc, domid, &libxl__vkb_devtype,
- &d_config->vkbs[i]);
- }
-
if (d_config->b_info.arch_arm.vuart == LIBXL_VUART_TYPE_SBSA_UART) {
init_console_info(gc, &vuart, 0);
vuart.backend_domid = state->console_domid;
--
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