Hi
On Mon, Mar 7, 2016 at 8:25 PM, Markus Armbruster <arm...@redhat.com> wrote:
> There are three predicates related to MSI-X:
>
> * ivshmem_has_feature(s, IVSHMEM_MSI) is true unless the non-MSI-X
> variant of the device is selected with msi=off.
>
> * msix_present() is true when the device has the PCI capability MSI-X.
> It's initially false, and becomes true during successful realize of
> the MSI-X variant of the device. Thus, it's the same as
> ivshmem_has_feature(s, IVSHMEM_MSI) for realized devices.
>
> * msix_enabled() is true when msix_present() is true and guest software
> has enabled MSI-X.
>
> Code that differs between the non-MSI-X and the MSI-X variant of the
> device needs to be guarded by ivshmem_has_feature(s, IVSHMEM_MSI) or
> by msix_present(), except the latter works only for realized devices.
>
> Code that depends on whether MSI-X is in use needs to be guarded with
> msix_enabled().
>
> Code review led me to two minor messes:
>
> * ivshmem_vector_notify() calls msix_notify() even when
> !msix_enabled(), unlike most other MSI-X-capable devices. As far as
> I can tell, msix_notify() does nothing when !msix_enabled(). Add
> the guard anyway.
>
> * Most callers of ivshmem_use_msix() guard it with
> ivshmem_has_feature(s, IVSHMEM_MSI). Not necessary, because
> ivshmem_use_msix() does nothing when !msix_present(). That's
> ivshmem's only use of msix_present(), though. Rename
> ivshmem_use_msix() to ivshmem_vector_use(), replace msix_present()
> by ivshmem_has_feature() there, and drop the redundant guards.
>
> Signed-off-by: Markus Armbruster <arm...@redhat.com>
> ---
> hw/misc/ivshmem.c | 22 +++++++++-------------
> 1 file changed, 9 insertions(+), 13 deletions(-)
>
> diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
> index 7191914..cfea151 100644
> --- a/hw/misc/ivshmem.c
> +++ b/hw/misc/ivshmem.c
> @@ -274,7 +274,9 @@ static void ivshmem_vector_notify(void *opaque)
>
> IVSHMEM_DPRINTF("interrupt on vector %p %d\n", pdev, vector);
> if (ivshmem_has_feature(s, IVSHMEM_MSI)) {
> - msix_notify(pdev, vector);
> + if (msix_enabled(pdev)) {
> + msix_notify(pdev, vector);
> + }
> } else {
> ivshmem_IntrStatus_write(s, 1);
> }
> @@ -712,13 +714,12 @@ static void ivshmem_check_version(void *opaque, const
> uint8_t * buf, int size)
> /* Select the MSI-X vectors used by device.
> * ivshmem maps events to vectors statically, so
> * we just enable all vectors on init and after reset. */
> -static void ivshmem_use_msix(IVShmemState * s)
> +static void ivshmem_vector_use(IVShmemState *s)
> {
> PCIDevice *d = PCI_DEVICE(s);
> int i;
>
> - IVSHMEM_DPRINTF("%s, msix present: %d\n", __func__, msix_present(d));
> - if (!msix_present(d)) {
> + if (!ivshmem_has_feature(s, IVSHMEM_MSI)) {
> return;
> }
>
> @@ -733,7 +734,7 @@ static void ivshmem_reset(DeviceState *d)
>
> s->intrstatus = 0;
> s->intrmask = 0;
> - ivshmem_use_msix(s);
> + ivshmem_vector_use(s);
> }
>
> static int ivshmem_setup_interrupts(IVShmemState *s)
> @@ -747,9 +748,9 @@ static int ivshmem_setup_interrupts(IVShmemState *s)
> }
>
> IVSHMEM_DPRINTF("msix initialized (%d vectors)\n", s->vectors);
> - ivshmem_use_msix(s);
> }
>
> + ivshmem_vector_use(s);
> return 0;
> }
>
> @@ -1034,12 +1035,7 @@ static int ivshmem_pre_load(void *opaque)
>
> static int ivshmem_post_load(void *opaque, int version_id)
> {
> - IVShmemState *s = opaque;
> -
> - if (ivshmem_has_feature(s, IVSHMEM_MSI)) {
> - ivshmem_use_msix(s);
> - }
> -
> + ivshmem_vector_use(opaque);
> return 0;
> }
>
> @@ -1067,11 +1063,11 @@ static int ivshmem_load_old(QEMUFile *f, void
> *opaque, int version_id)
>
> if (ivshmem_has_feature(s, IVSHMEM_MSI)) {
> msix_load(pdev, f);
> - ivshmem_use_msix(s);
> } else {
> s->intrstatus = qemu_get_be32(f);
> s->intrmask = qemu_get_be32(f);
> }
> + ivshmem_vector_use(s);
>
Sorry I didn't reply to your previous mail (which was slightly
confusing due to wrong naming), yes I think calling it
ivshmem_msix_vectors_use() inside the msix block is better (#2 from
your reply).
Other than that
Reviewed-by: Marc-André Lureau <marcandre.lur...@redhat.com>
--
Marc-André Lureau
