[PATCH v6 15/17] hw/vfio/pci: Omit errp for pci_add_capability

From: Akihiko Odaki <akihiko.odaki@daynix.com>
Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org,
	qemu-arm@nongnu.org, "Michael S . Tsirkin" <mst@redhat.com>,
	Marcel Apfelbaum <marcel.apfelbaum@gmail.com>,
	Gerd Hoffmann <kraxel@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Richard Henderson <richard.henderson@linaro.org>,
	Eduardo Habkost <eduardo@habkost.net>,
	John Snow <jsnow@redhat.com>,
	Dmitry Fleytman <dmitry.fleytman@gmail.com>,
	Jason Wang <jasowang@redhat.com>, Stefan Weil <sw@weilnetz.de>,
	Keith Busch <kbusch@kernel.org>, Klaus Jensen <its@irrelevant.dk>,
	Peter Maydell <peter.maydell@linaro.org>,
	Andrey Smirnov <andrew.smirnov@gmail.com>,
	Paul Burton <paulburton@kernel.org>,
	Aleksandar Rikalo <aleksandar.rikalo@syrmia.com>,
	Yan Vugenfirer <yan@daynix.com>,
	Yuri Benditovich <yuri.benditovich@daynix.com>,
	Akihiko Odaki <akihiko.odaki@daynix.com>
Subject: [PATCH v6 15/17] hw/vfio/pci: Omit errp for pci_add_capability
Date: Mon, 31 Oct 2022 21:33:17 +0900	[thread overview]
Message-ID: <20221031123319.21532-16-akihiko.odaki@daynix.com> (raw)
In-Reply-To: <20221031123319.21532-1-akihiko.odaki@daynix.com>

The code generating errors in pci_add_capability has a comment which
says:
> Verify that capabilities don't overlap.  Note: device assignment
> depends on this check to verify that the device is not broken.
> Should never trigger for emulated devices, but it's helpful for
> debugging these.

Indeed vfio has some code that passes capability offsets and sizes from
a physical device, but it explicitly pays attention so that the
capabilities never overlap. Therefore, in pci_add_capability(), we can
always assert that capabilities never overlap, and that is what happens
when omitting errp.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
---
 hw/vfio/pci-quirks.c | 15 +++------------
 hw/vfio/pci.c        | 14 +++++---------
 2 files changed, 8 insertions(+), 21 deletions(-)

diff --git a/hw/vfio/pci-quirks.c b/hw/vfio/pci-quirks.c
index f0147a050a..e94fd273ea 100644
--- a/hw/vfio/pci-quirks.c
+++ b/hw/vfio/pci-quirks.c
@@ -1530,7 +1530,7 @@ const PropertyInfo qdev_prop_nv_gpudirect_clique = {
 static int vfio_add_nv_gpudirect_cap(VFIOPCIDevice *vdev, Error **errp)
 {
     PCIDevice *pdev = &vdev->pdev;
-    int ret, pos = 0xC8;
+    int pos = 0xC8;
 
     if (vdev->nv_gpudirect_clique == 0xFF) {
         return 0;
@@ -1547,11 +1547,7 @@ static int vfio_add_nv_gpudirect_cap(VFIOPCIDevice *vdev, Error **errp)
         return -EINVAL;
     }
 
-    ret = pci_add_capability(pdev, PCI_CAP_ID_VNDR, pos, 8, errp);
-    if (ret < 0) {
-        error_prepend(errp, "Failed to add NVIDIA GPUDirect cap: ");
-        return ret;
-    }
+    pci_add_capability(pdev, PCI_CAP_ID_VNDR, pos, 8);
 
     memset(vdev->emulated_config_bits + pos, 0xFF, 8);
     pos += PCI_CAP_FLAGS;
@@ -1718,12 +1714,7 @@ static int vfio_add_vmd_shadow_cap(VFIOPCIDevice *vdev, Error **errp)
         return -EFAULT;
     }
 
-    ret = pci_add_capability(&vdev->pdev, PCI_CAP_ID_VNDR, pos,
-                             VMD_SHADOW_CAP_LEN, errp);
-    if (ret < 0) {
-        error_prepend(errp, "Failed to add VMD MEMBAR Shadow cap: ");
-        return ret;
-    }
+    pci_add_capability(&vdev->pdev, PCI_CAP_ID_VNDR, pos, VMD_SHADOW_CAP_LEN);
 
     memset(vdev->emulated_config_bits + pos, 0xFF, VMD_SHADOW_CAP_LEN);
     pos += PCI_CAP_FLAGS;
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index c7e3ef95a7..cad5850f5e 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -1845,7 +1845,7 @@ static void vfio_add_emulated_long(VFIOPCIDevice *vdev, int pos,
     vfio_set_long_bits(vdev->emulated_config_bits + pos, mask, mask);
 }
 
-static int vfio_setup_pcie_cap(VFIOPCIDevice *vdev, int pos, uint8_t size,
+static int vfio_setup_pcie_cap(VFIOPCIDevice *vdev, uint8_t pos, uint8_t size,
                                Error **errp)
 {
     uint16_t flags;
@@ -1962,11 +1962,7 @@ static int vfio_setup_pcie_cap(VFIOPCIDevice *vdev, int pos, uint8_t size,
                                1, PCI_EXP_FLAGS_VERS);
     }
 
-    pos = pci_add_capability(&vdev->pdev, PCI_CAP_ID_EXP, pos, size,
-                             errp);
-    if (pos < 0) {
-        return pos;
-    }
+    pos = pci_add_capability(&vdev->pdev, PCI_CAP_ID_EXP, pos, size);
 
     vdev->pdev.exp.exp_cap = pos;
 
@@ -2080,14 +2076,14 @@ static int vfio_add_std_cap(VFIOPCIDevice *vdev, uint8_t pos, Error **errp)
     case PCI_CAP_ID_PM:
         vfio_check_pm_reset(vdev, pos);
         vdev->pm_cap = pos;
-        ret = pci_add_capability(pdev, cap_id, pos, size, errp);
+        pci_add_capability(pdev, cap_id, pos, size);
         break;
     case PCI_CAP_ID_AF:
         vfio_check_af_flr(vdev, pos);
-        ret = pci_add_capability(pdev, cap_id, pos, size, errp);
+        pci_add_capability(pdev, cap_id, pos, size);
         break;
     default:
-        ret = pci_add_capability(pdev, cap_id, pos, size, errp);
+        pci_add_capability(pdev, cap_id, pos, size);
         break;
     }
 
-- 
2.38.1


