On Thu, Jul 20, 2023 at 12:32:34AM +0000, Volodymyr Babchuk wrote: > From: Oleksandr Andrushchenko <[email protected]> > > There are three originators for the PCI configuration space access: > 1. The domain that owns physical host bridge: MMIO handlers are > there so we can update vPCI register handlers with the values > written by the hardware domain, e.g. physical view of the registers > vs guest's view on the configuration space. > 2. Guest access to the passed through PCI devices: we need to properly > map virtual bus topology to the physical one, e.g. pass the configuration > space access to the corresponding physical devices. > 3. Emulated host PCI bridge access. It doesn't exist in the physical > topology, e.g. it can't be mapped to some physical host bridge. > So, all access to the host bridge itself needs to be trapped and > emulated. > > Signed-off-by: Oleksandr Andrushchenko <[email protected]> > --- > Since v8: > - locks moved out of vpci_translate_virtual_device() > Since v6: > - add pcidevs locking to vpci_translate_virtual_device > - update wrt to the new locking scheme > Since v5: > - add vpci_translate_virtual_device for #ifndef CONFIG_HAS_VPCI_GUEST_SUPPORT > case to simplify ifdefery > - add ASSERT(!is_hardware_domain(d)); to vpci_translate_virtual_device > - reset output register on failed virtual SBDF translation > Since v4: > - indentation fixes > - constify struct domain > - updated commit message > - updates to the new locking scheme (pdev->vpci_lock) > Since v3: > - revisit locking > - move code to vpci.c > Since v2: > - pass struct domain instead of struct vcpu > - constify arguments where possible > - gate relevant code with CONFIG_HAS_VPCI_GUEST_SUPPORT > New in v2 > --- > xen/arch/arm/vpci.c | 47 +++++++++++++++++++++++++++++++++++++++-- > xen/drivers/vpci/vpci.c | 24 +++++++++++++++++++++ > xen/include/xen/vpci.h | 7 ++++++ > 3 files changed, 76 insertions(+), 2 deletions(-) > > diff --git a/xen/arch/arm/vpci.c b/xen/arch/arm/vpci.c > index 3bc4bb5508..66701465af 100644 > --- a/xen/arch/arm/vpci.c > +++ b/xen/arch/arm/vpci.c > @@ -28,10 +28,33 @@ static int vpci_mmio_read(struct vcpu *v, mmio_info_t > *info, > register_t *r, void *p) > { > struct pci_host_bridge *bridge = p; > - pci_sbdf_t sbdf = vpci_sbdf_from_gpa(bridge, info->gpa); > + pci_sbdf_t sbdf; > /* data is needed to prevent a pointer cast on 32bit */ > unsigned long data; > > + ASSERT(!bridge == !is_hardware_domain(v->domain)); > + > + sbdf = vpci_sbdf_from_gpa(bridge, info->gpa); > + > + /* > + * For the passed through devices we need to map their virtual SBDF > + * to the physical PCI device being passed through. > + */ > + if ( !bridge ) > + { > + bool translated; > + > + read_lock(&v->domain->pci_lock); > + translated = vpci_translate_virtual_device(v->domain, &sbdf); > + read_unlock(&v->domain->pci_lock); > + > + if ( !translated ) > + { > + *r = ~0ul; > + return 1; > + } > + }
I've been thinking about this, is there any reason to not place this logic inside of vpci_sbdf_from_gpa()? I'm not sure you need to expose vpci_translate_virtual_device(). Thanks, Roger.
