Re: [Qemu-devel] [PATCH] e1000e: remove internal interrupt flag

[Markus Armbruster <armbru@redhat.com>]

Dmitry Fleytman <dmitry@daynix.com> writes:

>> On 18 Aug 2016, at 17:15, Cao jin <caoj.fnst@cn.fujitsu.com> wrote:
>> 
>> Commit 66bf7d58 removed internal msi state flag E1000E_USE_MSI, E1000E_USE_MSIX
>> is not necessary too, remove it now. And interrupt flag field intr_state also
>> can be removed now.
>> 
>> CC: Dmitry Fleytman <dmitry@daynix.com>
>> CC: Jason Wang <jasowang@redhat.com>
>> CC: Markus Armbruster <armbru@redhat.com>
>> CC: Marcel Apfelbaum <marcel@redhat.com>
>> CC: Michael S. Tsirkin <mst@redhat.com>
>> CC: Paolo Bonzini <pbonzini@redhat.com>
>> Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
>> ---
>> hw/net/e1000e.c | 8 +-------
>> 1 file changed, 1 insertion(+), 7 deletions(-)
>> 
>> diff --git a/hw/net/e1000e.c b/hw/net/e1000e.c
>> index 82a7be1..72aad21 100644
>> --- a/hw/net/e1000e.c
>> +++ b/hw/net/e1000e.c
>> @@ -69,7 +69,6 @@ typedef struct E1000EState {
>>     uint16_t subsys_ven_used;
>>     uint16_t subsys_used;
>> 
>> -    uint32_t intr_state;
>>     bool disable_vnet;
>> 
>>     E1000ECore core;
>> @@ -89,8 +88,6 @@ typedef struct E1000EState {
>> #define E1000E_MSIX_TABLE   (0x0000)
>> #define E1000E_MSIX_PBA     (0x2000)
>> 
>> -#define E1000E_USE_MSIX    BIT(0)
>> -
>> static uint64_t
>> e1000e_mmio_read(void *opaque, hwaddr addr, unsigned size)
>> {
>> @@ -302,8 +299,6 @@ e1000e_init_msix(E1000EState *s)
>>     } else {
>>         if (!e1000e_use_msix_vectors(s, E1000E_MSIX_VEC_NUM)) {
>>             msix_uninit(d, &s->msix, &s->msix);
>> -        } else {
>> -            s->intr_state |= E1000E_USE_MSIX;
>
> So you are removing error handling here. But what if e1000e_use_msix_vectors fails?

Before the patch, E1000E_USE_MSIX is set exactly when MSI-X was enabled
successfully.  It's only use is in MSI-X cleanup (next hunk): cleanup is
skipped when the flag isn't set.

The flag is pointless, because we can just as well test whether MSI-X is
enabled directly.  That's what the patch does.

>
>>         }
>>     }
>> }
>> @@ -311,7 +306,7 @@ e1000e_init_msix(E1000EState *s)
>> static void
>> e1000e_cleanup_msix(E1000EState *s)
>> {
>> -    if (s->intr_state & E1000E_USE_MSIX) {
>> +    if (msix_enabled(PCI_DEVICE(s))) {
>>         e1000e_unuse_msix_vectors(s, E1000E_MSIX_VEC_NUM);
>>         msix_uninit(PCI_DEVICE(s), &s->msix, &s->msix);
>>     }
>> @@ -601,7 +596,6 @@ static const VMStateDescription e1000e_vmstate = {
>>         VMSTATE_MSIX(parent_obj, E1000EState),
>> 
>>         VMSTATE_UINT32(ioaddr, E1000EState),
>> -       VMSTATE_UINT32(intr_state, E1000EState),

We can still do this, because as Paolo pointed out, no released version
of QEMU had this device.

>>         VMSTATE_UINT32(core.rxbuf_min_shift, E1000EState),
>>         VMSTATE_UINT8(core.rx_desc_len, E1000EState),
>>         VMSTATE_UINT32_ARRAY(core.rxbuf_sizes, E1000EState,
>> -- 
>> 2.1.0

Reviewed-by: Markus Armbruster <armbru@redhat.com>