[PULL 25/25] hw/ide/ahci: trigger either error IRQ or regular IRQ, not both

[Kevin Wolf <kwolf@redhat.com>]

From: Niklas Cassel <niklas.cassel@wdc.com>

According to AHCI 1.3.1, 5.3.8.1 RegFIS:Entry, if ERR_STAT is set,
we jump to state ERR:FatalTaskfile, which will raise a TFES IRQ
unconditionally, regardless if the I bit is set in the FIS or not.

Thus, we should never raise a normal IRQ after having sent an error
IRQ.

NOTE: for QEMU platforms that use SeaBIOS, this patch depends on QEMU
commit 784155cdcb02 ("seabios: update submodule to git snapshot"), and
QEMU commit 14f5a7bae4cb ("seabios: update binaries to git snapshot"),
which update SeaBIOS to a version that contains SeaBIOS commit 1281e340
("ahci: handle TFES irq correctly").

Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
Message-ID: <20231011131220.1992064-1-nks@flawful.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 hw/ide/ahci.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
index fcc5476e9e..7676e2d871 100644
--- a/hw/ide/ahci.c
+++ b/hw/ide/ahci.c
@@ -897,11 +897,10 @@ static bool ahci_write_fis_d2h(AHCIDevice *ad, bool d2h_fis_i)
     pr->tfdata = (ad->port.ifs[0].error << 8) |
         ad->port.ifs[0].status;
 
+    /* TFES IRQ is always raised if ERR_STAT is set, regardless of I bit. */
     if (d2h_fis[2] & ERR_STAT) {
         ahci_trigger_irq(ad->hba, ad, AHCI_PORT_IRQ_BIT_TFES);
-    }
-
-    if (d2h_fis_i) {
+    } else if (d2h_fis_i) {
         ahci_trigger_irq(ad->hba, ad, AHCI_PORT_IRQ_BIT_DHRS);
     }
 
-- 
2.41.0