Re: [Qemu-devel] [PATCH 1/8] libqos: Give qvirtio_config_read*() consistent semantics

2016-10-18 Thread David Gibson 
On Tue, Oct 18, 2016 at 03:27:09PM +0200, Greg Kurz wrote:
> On Tue, 18 Oct 2016 21:52:06 +1100
> David Gibson  wrote:
> 
> > The 'addr' parameter to qvirtio_config_read*() doesn't have a consistent
> > meaning: when using the virtio-pci versions, it's a full PCI space address,
> > but for virtio-mmio, it's an offset from the device's base mmio address.
> > 
> > This means that the callers need to do different things to calculate the
> > addresses in the two cases, which rather defeats the purpose of function
> > pointer backends.
> > 
> > All the current users of these functions are using them to retrieve
> > variables from the device specific portion of the virtio config space.
> > So, this patch alters the semantics to always be an offset into that
> > device specific config area.
> > 
> > Signed-off-by: David Gibson 
> > ---
> >  tests/libqos/virtio-mmio.c | 16 +++
> >  tests/libqos/virtio-pci.c  | 22 
> >  tests/virtio-9p-test.c |  9 ++--
> >  tests/virtio-blk-test.c| 51 
> > ++
> >  tests/virtio-scsi-test.c   |  5 +
> >  5 files changed, 35 insertions(+), 68 deletions(-)
> > 
> > diff --git a/tests/libqos/virtio-mmio.c b/tests/libqos/virtio-mmio.c
> > index 0cab38f..b0b74dc 100644
> > --- a/tests/libqos/virtio-mmio.c
> > +++ b/tests/libqos/virtio-mmio.c
> > @@ -15,28 +15,28 @@
> >  #include "libqos/malloc-generic.h"
> >  #include "standard-headers/linux/virtio_ring.h"
> >  
> > -static uint8_t qvirtio_mmio_config_readb(QVirtioDevice *d, uint64_t addr)
> > +static uint8_t qvirtio_mmio_config_readb(QVirtioDevice *d, uint64_t off)
> >  {
> >  QVirtioMMIODevice *dev = (QVirtioMMIODevice *)d;
> > -return readb(dev->addr + addr);
> > +return readb(dev->addr + QVIRTIO_MMIO_DEVICE_SPECIFIC + off);
> >  }
> >  
> > -static uint16_t qvirtio_mmio_config_readw(QVirtioDevice *d, uint64_t addr)
> > +static uint16_t qvirtio_mmio_config_readw(QVirtioDevice *d, uint64_t off)
> >  {
> >  QVirtioMMIODevice *dev = (QVirtioMMIODevice *)d;
> > -return readw(dev->addr + addr);
> > +return readw(dev->addr + QVIRTIO_MMIO_DEVICE_SPECIFIC + off);
> >  }
> >  
> > -static uint32_t qvirtio_mmio_config_readl(QVirtioDevice *d, uint64_t addr)
> > +static uint32_t qvirtio_mmio_config_readl(QVirtioDevice *d, uint64_t off)
> >  {
> >  QVirtioMMIODevice *dev = (QVirtioMMIODevice *)d;
> > -return readl(dev->addr + addr);
> > +return readl(dev->addr + QVIRTIO_MMIO_DEVICE_SPECIFIC + off);
> >  }
> >  
> > -static uint64_t qvirtio_mmio_config_readq(QVirtioDevice *d, uint64_t addr)
> > +static uint64_t qvirtio_mmio_config_readq(QVirtioDevice *d, uint64_t off)
> >  {
> >  QVirtioMMIODevice *dev = (QVirtioMMIODevice *)d;
> > -return readq(dev->addr + addr);
> > +return readq(dev->addr + QVIRTIO_MMIO_DEVICE_SPECIFIC + off);
> >  }
> >  
> >  static uint32_t qvirtio_mmio_get_features(QVirtioDevice *d)
> > diff --git a/tests/libqos/virtio-pci.c b/tests/libqos/virtio-pci.c
> > index 6e005c1..8037724 100644
> > --- a/tests/libqos/virtio-pci.c
> > +++ b/tests/libqos/virtio-pci.c
> > @@ -62,39 +62,43 @@ static void qvirtio_pci_assign_device(QVirtioDevice *d, 
> > void *data)
> >  *vpcidev = (QVirtioPCIDevice *)d;
> >  }
> >  
> > -static uint8_t qvirtio_pci_config_readb(QVirtioDevice *d, uint64_t addr)
> > +static uint8_t qvirtio_pci_config_readb(QVirtioDevice *d, uint64_t off)
> >  {
> >  QVirtioPCIDevice *dev = (QVirtioPCIDevice *)d;
> > -return qpci_io_readb(dev->pdev, (void *)(uintptr_t)addr);
> > +void *base = dev->addr + 
> > VIRTIO_PCI_CONFIG_OFF(dev->pdev->msix_enabled);
> 
> $ git grep VIRTIO_PCI_CONFIG_OFF tests
> tests/libqos/virtio-pci.c:void *base = dev->addr + 
> VIRTIO_PCI_CONFIG_OFF(dev->pdev->msix_enabled);
> tests/libqos/virtio-pci.c:void *base = dev->addr + 
> VIRTIO_PCI_CONFIG_OFF(dev->pdev->msix_enabled);
> tests/libqos/virtio-pci.c:void *base = dev->addr + 
> VIRTIO_PCI_CONFIG_OFF(dev->pdev->msix_enabled);
> tests/libqos/virtio-pci.c:void *base = dev->addr + 
> VIRTIO_PCI_CONFIG_OFF(dev->pdev->msix_enabled);
> 
> Maybe this could be consolidated into a helper ?

Good idea, I'll add a macro.

> 
> Either way works for me since it is a definite improvement over what we 
> currently have:
> 
> Reviewed-by: Greg Kurz 
> 
> > +return qpci_io_readb(dev->pdev, base + off);
> >  }
> >  
> > -static uint16_t qvirtio_pci_config_readw(QVirtioDevice *d, uint64_t addr)
> > +static uint16_t qvirtio_pci_config_readw(QVirtioDevice *d, uint64_t off)
> >  {
> >  QVirtioPCIDevice *dev = (QVirtioPCIDevice *)d;
> > -return qpci_io_readw(dev->pdev, (void *)(uintptr_t)addr);
> > +void *base = dev->addr + 
> > VIRTIO_PCI_CONFIG_OFF(dev->pdev->msix_enabled);
> > +return qpci_io_readw(dev->pdev, base + off);
> >  }
> >  
> > -static uint32_t qvirtio_pci_config_readl(QVirtioDevice *d,

Re: [Qemu-devel] [PATCH 1/8] libqos: Give qvirtio_config_read*() consistent semantics

2016-10-18 Thread Greg Kurz 
On Tue, 18 Oct 2016 21:52:06 +1100
David Gibson  wrote:

> The 'addr' parameter to qvirtio_config_read*() doesn't have a consistent
> meaning: when using the virtio-pci versions, it's a full PCI space address,
> but for virtio-mmio, it's an offset from the device's base mmio address.
> 
> This means that the callers need to do different things to calculate the
> addresses in the two cases, which rather defeats the purpose of function
> pointer backends.
> 
> All the current users of these functions are using them to retrieve
> variables from the device specific portion of the virtio config space.
> So, this patch alters the semantics to always be an offset into that
> device specific config area.
> 
> Signed-off-by: David Gibson 
> ---
>  tests/libqos/virtio-mmio.c | 16 +++
>  tests/libqos/virtio-pci.c  | 22 
>  tests/virtio-9p-test.c |  9 ++--
>  tests/virtio-blk-test.c| 51 
> ++
>  tests/virtio-scsi-test.c   |  5 +
>  5 files changed, 35 insertions(+), 68 deletions(-)
> 
> diff --git a/tests/libqos/virtio-mmio.c b/tests/libqos/virtio-mmio.c
> index 0cab38f..b0b74dc 100644
> --- a/tests/libqos/virtio-mmio.c
> +++ b/tests/libqos/virtio-mmio.c
> @@ -15,28 +15,28 @@
>  #include "libqos/malloc-generic.h"
>  #include "standard-headers/linux/virtio_ring.h"
>  
> -static uint8_t qvirtio_mmio_config_readb(QVirtioDevice *d, uint64_t addr)
> +static uint8_t qvirtio_mmio_config_readb(QVirtioDevice *d, uint64_t off)
>  {
>  QVirtioMMIODevice *dev = (QVirtioMMIODevice *)d;
> -return readb(dev->addr + addr);
> +return readb(dev->addr + QVIRTIO_MMIO_DEVICE_SPECIFIC + off);
>  }
>  
> -static uint16_t qvirtio_mmio_config_readw(QVirtioDevice *d, uint64_t addr)
> +static uint16_t qvirtio_mmio_config_readw(QVirtioDevice *d, uint64_t off)
>  {
>  QVirtioMMIODevice *dev = (QVirtioMMIODevice *)d;
> -return readw(dev->addr + addr);
> +return readw(dev->addr + QVIRTIO_MMIO_DEVICE_SPECIFIC + off);
>  }
>  
> -static uint32_t qvirtio_mmio_config_readl(QVirtioDevice *d, uint64_t addr)
> +static uint32_t qvirtio_mmio_config_readl(QVirtioDevice *d, uint64_t off)
>  {
>  QVirtioMMIODevice *dev = (QVirtioMMIODevice *)d;
> -return readl(dev->addr + addr);
> +return readl(dev->addr + QVIRTIO_MMIO_DEVICE_SPECIFIC + off);
>  }
>  
> -static uint64_t qvirtio_mmio_config_readq(QVirtioDevice *d, uint64_t addr)
> +static uint64_t qvirtio_mmio_config_readq(QVirtioDevice *d, uint64_t off)
>  {
>  QVirtioMMIODevice *dev = (QVirtioMMIODevice *)d;
> -return readq(dev->addr + addr);
> +return readq(dev->addr + QVIRTIO_MMIO_DEVICE_SPECIFIC + off);
>  }
>  
>  static uint32_t qvirtio_mmio_get_features(QVirtioDevice *d)
> diff --git a/tests/libqos/virtio-pci.c b/tests/libqos/virtio-pci.c
> index 6e005c1..8037724 100644
> --- a/tests/libqos/virtio-pci.c
> +++ b/tests/libqos/virtio-pci.c
> @@ -62,39 +62,43 @@ static void qvirtio_pci_assign_device(QVirtioDevice *d, 
> void *data)
>  *vpcidev = (QVirtioPCIDevice *)d;
>  }
>  
> -static uint8_t qvirtio_pci_config_readb(QVirtioDevice *d, uint64_t addr)
> +static uint8_t qvirtio_pci_config_readb(QVirtioDevice *d, uint64_t off)
>  {
>  QVirtioPCIDevice *dev = (QVirtioPCIDevice *)d;
> -return qpci_io_readb(dev->pdev, (void *)(uintptr_t)addr);
> +void *base = dev->addr + VIRTIO_PCI_CONFIG_OFF(dev->pdev->msix_enabled);

$ git grep VIRTIO_PCI_CONFIG_OFF tests
tests/libqos/virtio-pci.c:void *base = dev->addr + 
VIRTIO_PCI_CONFIG_OFF(dev->pdev->msix_enabled);
tests/libqos/virtio-pci.c:void *base = dev->addr + 
VIRTIO_PCI_CONFIG_OFF(dev->pdev->msix_enabled);
tests/libqos/virtio-pci.c:void *base = dev->addr + 
VIRTIO_PCI_CONFIG_OFF(dev->pdev->msix_enabled);
tests/libqos/virtio-pci.c:void *base = dev->addr + 
VIRTIO_PCI_CONFIG_OFF(dev->pdev->msix_enabled);

Maybe this could be consolidated into a helper ?

Either way works for me since it is a definite improvement over what we 
currently have:

Reviewed-by: Greg Kurz 

> +return qpci_io_readb(dev->pdev, base + off);
>  }
>  
> -static uint16_t qvirtio_pci_config_readw(QVirtioDevice *d, uint64_t addr)
> +static uint16_t qvirtio_pci_config_readw(QVirtioDevice *d, uint64_t off)
>  {
>  QVirtioPCIDevice *dev = (QVirtioPCIDevice *)d;
> -return qpci_io_readw(dev->pdev, (void *)(uintptr_t)addr);
> +void *base = dev->addr + VIRTIO_PCI_CONFIG_OFF(dev->pdev->msix_enabled);
> +return qpci_io_readw(dev->pdev, base + off);
>  }
>  
> -static uint32_t qvirtio_pci_config_readl(QVirtioDevice *d, uint64_t addr)
> +static uint32_t qvirtio_pci_config_readl(QVirtioDevice *d, uint64_t off)
>  {
>  QVirtioPCIDevice *dev = (QVirtioPCIDevice *)d;
> -return qpci_io_readl(dev->pdev, (void *)(uintptr_t)addr);
> +void *base = dev->addr + VIRTIO_PCI_CONFIG_OFF(dev->pdev->msix_enabled);
> +return qpci_io_readl(dev->pdev,

Re: [Qemu-devel] [PATCH 1/8] libqos: Give qvirtio_config_read*() consistent semantics

2016-10-18 Thread Laurent Vivier 


On 18/10/2016 12:52, David Gibson wrote:
> The 'addr' parameter to qvirtio_config_read*() doesn't have a consistent
> meaning: when using the virtio-pci versions, it's a full PCI space address,
> but for virtio-mmio, it's an offset from the device's base mmio address.
> 
> This means that the callers need to do different things to calculate the
> addresses in the two cases, which rather defeats the purpose of function
> pointer backends.
> 
> All the current users of these functions are using them to retrieve
> variables from the device specific portion of the virtio config space.
> So, this patch alters the semantics to always be an offset into that
> device specific config area.
> 
> Signed-off-by: David Gibson 

Reviewed-by: Laurent Vivier 

> ---
>  tests/libqos/virtio-mmio.c | 16 +++
>  tests/libqos/virtio-pci.c  | 22 
>  tests/virtio-9p-test.c |  9 ++--
>  tests/virtio-blk-test.c| 51 
> ++
>  tests/virtio-scsi-test.c   |  5 +
>  5 files changed, 35 insertions(+), 68 deletions(-)
> 
> diff --git a/tests/libqos/virtio-mmio.c b/tests/libqos/virtio-mmio.c
> index 0cab38f..b0b74dc 100644
> --- a/tests/libqos/virtio-mmio.c
> +++ b/tests/libqos/virtio-mmio.c
> @@ -15,28 +15,28 @@
>  #include "libqos/malloc-generic.h"
>  #include "standard-headers/linux/virtio_ring.h"
>  
> -static uint8_t qvirtio_mmio_config_readb(QVirtioDevice *d, uint64_t addr)
> +static uint8_t qvirtio_mmio_config_readb(QVirtioDevice *d, uint64_t off)
>  {
>  QVirtioMMIODevice *dev = (QVirtioMMIODevice *)d;
> -return readb(dev->addr + addr);
> +return readb(dev->addr + QVIRTIO_MMIO_DEVICE_SPECIFIC + off);
>  }
>  
> -static uint16_t qvirtio_mmio_config_readw(QVirtioDevice *d, uint64_t addr)
> +static uint16_t qvirtio_mmio_config_readw(QVirtioDevice *d, uint64_t off)
>  {
>  QVirtioMMIODevice *dev = (QVirtioMMIODevice *)d;
> -return readw(dev->addr + addr);
> +return readw(dev->addr + QVIRTIO_MMIO_DEVICE_SPECIFIC + off);
>  }
>  
> -static uint32_t qvirtio_mmio_config_readl(QVirtioDevice *d, uint64_t addr)
> +static uint32_t qvirtio_mmio_config_readl(QVirtioDevice *d, uint64_t off)
>  {
>  QVirtioMMIODevice *dev = (QVirtioMMIODevice *)d;
> -return readl(dev->addr + addr);
> +return readl(dev->addr + QVIRTIO_MMIO_DEVICE_SPECIFIC + off);
>  }
>  
> -static uint64_t qvirtio_mmio_config_readq(QVirtioDevice *d, uint64_t addr)
> +static uint64_t qvirtio_mmio_config_readq(QVirtioDevice *d, uint64_t off)
>  {
>  QVirtioMMIODevice *dev = (QVirtioMMIODevice *)d;
> -return readq(dev->addr + addr);
> +return readq(dev->addr + QVIRTIO_MMIO_DEVICE_SPECIFIC + off);
>  }
>  
>  static uint32_t qvirtio_mmio_get_features(QVirtioDevice *d)
> diff --git a/tests/libqos/virtio-pci.c b/tests/libqos/virtio-pci.c
> index 6e005c1..8037724 100644
> --- a/tests/libqos/virtio-pci.c
> +++ b/tests/libqos/virtio-pci.c
> @@ -62,39 +62,43 @@ static void qvirtio_pci_assign_device(QVirtioDevice *d, 
> void *data)
>  *vpcidev = (QVirtioPCIDevice *)d;
>  }
>  
> -static uint8_t qvirtio_pci_config_readb(QVirtioDevice *d, uint64_t addr)
> +static uint8_t qvirtio_pci_config_readb(QVirtioDevice *d, uint64_t off)
>  {
>  QVirtioPCIDevice *dev = (QVirtioPCIDevice *)d;
> -return qpci_io_readb(dev->pdev, (void *)(uintptr_t)addr);
> +void *base = dev->addr + VIRTIO_PCI_CONFIG_OFF(dev->pdev->msix_enabled);
> +return qpci_io_readb(dev->pdev, base + off);
>  }
>  
> -static uint16_t qvirtio_pci_config_readw(QVirtioDevice *d, uint64_t addr)
> +static uint16_t qvirtio_pci_config_readw(QVirtioDevice *d, uint64_t off)
>  {
>  QVirtioPCIDevice *dev = (QVirtioPCIDevice *)d;
> -return qpci_io_readw(dev->pdev, (void *)(uintptr_t)addr);
> +void *base = dev->addr + VIRTIO_PCI_CONFIG_OFF(dev->pdev->msix_enabled);
> +return qpci_io_readw(dev->pdev, base + off);
>  }
>  
> -static uint32_t qvirtio_pci_config_readl(QVirtioDevice *d, uint64_t addr)
> +static uint32_t qvirtio_pci_config_readl(QVirtioDevice *d, uint64_t off)
>  {
>  QVirtioPCIDevice *dev = (QVirtioPCIDevice *)d;
> -return qpci_io_readl(dev->pdev, (void *)(uintptr_t)addr);
> +void *base = dev->addr + VIRTIO_PCI_CONFIG_OFF(dev->pdev->msix_enabled);
> +return qpci_io_readl(dev->pdev, base + off);
>  }
>  
> -static uint64_t qvirtio_pci_config_readq(QVirtioDevice *d, uint64_t addr)
> +static uint64_t qvirtio_pci_config_readq(QVirtioDevice *d, uint64_t off)
>  {
>  QVirtioPCIDevice *dev = (QVirtioPCIDevice *)d;
>  int i;
>  uint64_t u64 = 0;
> +void *base = dev->addr + VIRTIO_PCI_CONFIG_OFF(dev->pdev->msix_enabled);
>  
>  if (target_big_endian()) {
>  for (i = 0; i < 8; ++i) {
>  u64 |= (uint64_t)qpci_io_readb(dev->pdev,
> -(void *)(uintptr_t)addr + i) << (7 - i) * 8;
> +   base + off + i) <<

[Qemu-devel] [PATCH 1/8] libqos: Give qvirtio_config_read*() consistent semantics

2016-10-18 Thread David Gibson 
The 'addr' parameter to qvirtio_config_read*() doesn't have a consistent
meaning: when using the virtio-pci versions, it's a full PCI space address,
but for virtio-mmio, it's an offset from the device's base mmio address.

This means that the callers need to do different things to calculate the
addresses in the two cases, which rather defeats the purpose of function
pointer backends.

All the current users of these functions are using them to retrieve
variables from the device specific portion of the virtio config space.
So, this patch alters the semantics to always be an offset into that
device specific config area.

Signed-off-by: David Gibson 
---
 tests/libqos/virtio-mmio.c | 16 +++
 tests/libqos/virtio-pci.c  | 22 
 tests/virtio-9p-test.c |  9 ++--
 tests/virtio-blk-test.c| 51 ++
 tests/virtio-scsi-test.c   |  5 +
 5 files changed, 35 insertions(+), 68 deletions(-)

diff --git a/tests/libqos/virtio-mmio.c b/tests/libqos/virtio-mmio.c
index 0cab38f..b0b74dc 100644
--- a/tests/libqos/virtio-mmio.c
+++ b/tests/libqos/virtio-mmio.c
@@ -15,28 +15,28 @@
 #include "libqos/malloc-generic.h"
 #include "standard-headers/linux/virtio_ring.h"
 
-static uint8_t qvirtio_mmio_config_readb(QVirtioDevice *d, uint64_t addr)
+static uint8_t qvirtio_mmio_config_readb(QVirtioDevice *d, uint64_t off)
 {
 QVirtioMMIODevice *dev = (QVirtioMMIODevice *)d;
-return readb(dev->addr + addr);
+return readb(dev->addr + QVIRTIO_MMIO_DEVICE_SPECIFIC + off);
 }
 
-static uint16_t qvirtio_mmio_config_readw(QVirtioDevice *d, uint64_t addr)
+static uint16_t qvirtio_mmio_config_readw(QVirtioDevice *d, uint64_t off)
 {
 QVirtioMMIODevice *dev = (QVirtioMMIODevice *)d;
-return readw(dev->addr + addr);
+return readw(dev->addr + QVIRTIO_MMIO_DEVICE_SPECIFIC + off);
 }
 
-static uint32_t qvirtio_mmio_config_readl(QVirtioDevice *d, uint64_t addr)
+static uint32_t qvirtio_mmio_config_readl(QVirtioDevice *d, uint64_t off)
 {
 QVirtioMMIODevice *dev = (QVirtioMMIODevice *)d;
-return readl(dev->addr + addr);
+return readl(dev->addr + QVIRTIO_MMIO_DEVICE_SPECIFIC + off);
 }
 
-static uint64_t qvirtio_mmio_config_readq(QVirtioDevice *d, uint64_t addr)
+static uint64_t qvirtio_mmio_config_readq(QVirtioDevice *d, uint64_t off)
 {
 QVirtioMMIODevice *dev = (QVirtioMMIODevice *)d;
-return readq(dev->addr + addr);
+return readq(dev->addr + QVIRTIO_MMIO_DEVICE_SPECIFIC + off);
 }
 
 static uint32_t qvirtio_mmio_get_features(QVirtioDevice *d)
diff --git a/tests/libqos/virtio-pci.c b/tests/libqos/virtio-pci.c
index 6e005c1..8037724 100644
--- a/tests/libqos/virtio-pci.c
+++ b/tests/libqos/virtio-pci.c
@@ -62,39 +62,43 @@ static void qvirtio_pci_assign_device(QVirtioDevice *d, 
void *data)
 *vpcidev = (QVirtioPCIDevice *)d;
 }
 
-static uint8_t qvirtio_pci_config_readb(QVirtioDevice *d, uint64_t addr)
+static uint8_t qvirtio_pci_config_readb(QVirtioDevice *d, uint64_t off)
 {
 QVirtioPCIDevice *dev = (QVirtioPCIDevice *)d;
-return qpci_io_readb(dev->pdev, (void *)(uintptr_t)addr);
+void *base = dev->addr + VIRTIO_PCI_CONFIG_OFF(dev->pdev->msix_enabled);
+return qpci_io_readb(dev->pdev, base + off);
 }
 
-static uint16_t qvirtio_pci_config_readw(QVirtioDevice *d, uint64_t addr)
+static uint16_t qvirtio_pci_config_readw(QVirtioDevice *d, uint64_t off)
 {
 QVirtioPCIDevice *dev = (QVirtioPCIDevice *)d;
-return qpci_io_readw(dev->pdev, (void *)(uintptr_t)addr);
+void *base = dev->addr + VIRTIO_PCI_CONFIG_OFF(dev->pdev->msix_enabled);
+return qpci_io_readw(dev->pdev, base + off);
 }
 
-static uint32_t qvirtio_pci_config_readl(QVirtioDevice *d, uint64_t addr)
+static uint32_t qvirtio_pci_config_readl(QVirtioDevice *d, uint64_t off)
 {
 QVirtioPCIDevice *dev = (QVirtioPCIDevice *)d;
-return qpci_io_readl(dev->pdev, (void *)(uintptr_t)addr);
+void *base = dev->addr + VIRTIO_PCI_CONFIG_OFF(dev->pdev->msix_enabled);
+return qpci_io_readl(dev->pdev, base + off);
 }
 
-static uint64_t qvirtio_pci_config_readq(QVirtioDevice *d, uint64_t addr)
+static uint64_t qvirtio_pci_config_readq(QVirtioDevice *d, uint64_t off)
 {
 QVirtioPCIDevice *dev = (QVirtioPCIDevice *)d;
 int i;
 uint64_t u64 = 0;
+void *base = dev->addr + VIRTIO_PCI_CONFIG_OFF(dev->pdev->msix_enabled);
 
 if (target_big_endian()) {
 for (i = 0; i < 8; ++i) {
 u64 |= (uint64_t)qpci_io_readb(dev->pdev,
-(void *)(uintptr_t)addr + i) << (7 - i) * 8;
+   base + off + i) << (7 - i) * 8;
 }
 } else {
 for (i = 0; i < 8; ++i) {
 u64 |= (uint64_t)qpci_io_readb(dev->pdev,
-(void *)(uintptr_t)addr + i) << i * 8;
+   base + off + i) << i * 8;
 }
 }
 
diff --git