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vfio/pci: Decouple PCI_COMMAND_MEMORY bit checks from is_virtfn 

While it is true that devices with is_virtfn=1 will have a Memory Space
Enable bit that is hard-wired to 0, this is not the only case where we
see this behavior -- For example some bare-metal hypervisors lack
Memory Space Enable bit emulation for devices not setting is_virtfn
(s390). Fix this by instead checking for the newly-added
no_command_memory bit which directly denotes the need for
PCI_COMMAND_MEMORY emulation in vfio.

Fixes: abafbc551f ("vfio-pci: Invalidate mmaps and block MMIO access on disabled memory")
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Matthew Rosato 2020-09-10 10:59:57 -04:00 committed by Alex Williamson
parent 08b6e22b85
commit 515ecd5368
1 changed files with 14 additions and 10 deletions
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24
drivers/vfio/pci/vfio_pci_config.c
View File

@ -406,7 +406,7 @@ bool __vfio_pci_memory_enabled(struct vfio_pci_device *vdev)
* PF SR-IOV capability, there's therefore no need to trigger
* faults based on the virtual value.
*/
return pdev->is_virtfn || (cmd & PCI_COMMAND_MEMORY);
return pdev->no_command_memory || (cmd & PCI_COMMAND_MEMORY);
}
/*
@ -520,8 +520,8 @@ static int vfio_basic_config_read(struct vfio_pci_device *vdev, int pos,
count = vfio_default_config_read(vdev, pos, count, perm, offset, val);
/* Mask in virtual memory enable for SR-IOV devices */
if (offset == PCI_COMMAND && vdev->pdev->is_virtfn) {
/* Mask in virtual memory enable */
if (offset == PCI_COMMAND && vdev->pdev->no_command_memory) {
u16 cmd = le16_to_cpu(*(__le16 *)&vdev->vconfig[PCI_COMMAND]);
u32 tmp_val = le32_to_cpu(*val);
@ -589,9 +589,11 @@ static int vfio_basic_config_write(struct vfio_pci_device *vdev, int pos,
* shows it disabled (phys_mem/io, then the device has
* undergone some kind of backdoor reset and needs to be
* restored before we allow it to enable the bars.
* SR-IOV devices will trigger this, but we catch them later
* SR-IOV devices will trigger this - for mem enable let's
* catch this now and for io enable it will be caught later
*/
if ((new_mem && virt_mem && !phys_mem) ||
if ((new_mem && virt_mem && !phys_mem &&
!pdev->no_command_memory) ||
(new_io && virt_io && !phys_io) ||
vfio_need_bar_restore(vdev))
vfio_bar_restore(vdev);
@ -1734,12 +1736,14 @@ int vfio_config_init(struct vfio_pci_device *vdev)
vconfig[PCI_INTERRUPT_PIN]);
vconfig[PCI_INTERRUPT_PIN] = 0; /* Gratuitous for good VFs */
}
if (pdev->no_command_memory) {
/*
* VFs do no implement the memory enable bit of the COMMAND
* register therefore we'll not have it set in our initial
* copy of config space after pci_enable_device(). For
* consistency with PFs, set the virtual enable bit here.
* VFs and devices that set pdev->no_command_memory do not
* implement the memory enable bit of the COMMAND register
* therefore we'll not have it set in our initial copy of
* config space after pci_enable_device(). For consistency
* with PFs, set the virtual enable bit here.
*/
*(__le16 *)&vconfig[PCI_COMMAND] |=
cpu_to_le16(PCI_COMMAND_MEMORY);