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ivshmem: Split ivshmem-plain, ivshmem-doorbell off ivshmem

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ivshmem can be configured with and without interrupt capability
(a.k.a. "doorbell").  The two configurations have largely disjoint
options, which makes for a confusing (and badly checked) user
interface.  Moreover, the device can't tell the guest whether its
doorbell is enabled.

Create two new device models ivshmem-plain and ivshmem-doorbell, and
deprecate the old one.

Changes from ivshmem:

* PCI revision is 1 instead of 0.  The new revision is fully backwards
  compatible for guests.  Guests may elect to require at least
  revision 1 to make sure they're not exposed to the funny "no shared
  memory, yet" state.

* Property "role" replaced by "master".  role=master becomes
  master=on, role=peer becomes master=off.  Default is off instead of
  auto.

* Property "use64" is gone.  The new devices always have 64 bit BARs.

Changes from ivshmem to ivshmem-plain:

* The Interrupt Pin register in PCI config space is zero (does not use
  an interrupt pin) instead of one (uses INTA).

* Property "x-memdev" is renamed to "memdev".

* Properties "shm" and "size" are gone.  Use property "memdev"
  instead.

* Property "msi" is gone.  The new device can't have MSI-X capability.
  It can't interrupt anyway.

* Properties "ioeventfd" and "vectors" are gone.  They're meaningless
  without interrupts anyway.

Changes from ivshmem to ivshmem-doorbell:

* Property "msi" is gone.  The new device always has MSI-X capability.

* Property "ioeventfd" defaults to on instead of off.

* Property "size" is gone.  The new device can only map all the shared
  memory received from the server.

Guests can easily find out whether the device is configured for
interrupts by checking for MSI-X capability.

Note: some code added in sub-optimal places to make the diff easier to
review.  The next commit will move it to more sensible places.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1458066895-20632-37-git-send-email-armbru@redhat.com>
This commit is contained in:
Markus Armbruster 2016-03-15 19:34:51 +01:00
parent 2a845da736
commit 5400c02b90
4 changed files with 308 additions and 140 deletions
Download patch file Download diff file Expand all files Collapse all files

12
tests/ivshmem-test.c
View file

@ -127,7 +127,9 @@ static void setup_vm_cmd(IVState *s, const char *cmd, bool msix)
static void setup_vm(IVState *s)
{
char *cmd = g_strdup_printf("-device ivshmem,shm=%s,size=1M", tmpshm);
char *cmd = g_strdup_printf("-object memory-backend-file"
",id=mb1,size=1M,share,mem-path=/dev/shm%s"
" -device ivshmem-plain,memdev=mb1", tmpshm);
setup_vm_cmd(s, cmd, false);
@ -284,8 +286,10 @@ static void *server_thread(void *data)
static void setup_vm_with_server(IVState *s, int nvectors, bool msi)
{
char *cmd = g_strdup_printf("-chardev socket,id=chr0,path=%s,nowait "
"-device ivshmem,size=1M,chardev=chr0,vectors=%d,msi=%s",
tmpserver, nvectors, msi ? "true" : "false");
"-device ivshmem%s,chardev=chr0,vectors=%d",
tmpserver,
msi ? "-doorbell" : ",size=1M,msi=off",
nvectors);
setup_vm_cmd(s, cmd, msi);
@ -412,7 +416,7 @@ static void test_ivshmem_memdev(void)
/* just for the sake of checking memory-backend property */
setup_vm_cmd(&state, "-object memory-backend-ram,size=1M,id=mb1"
" -device ivshmem,x-memdev=mb1", false);
" -device ivshmem-plain,memdev=mb1", false);
cleanup_vm(&state);
}