[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH v5 12/14] xen/arm: translate virtual PCI bus topology for guests
On Thu, Nov 25, 2021 at 01:02:49PM +0200, Oleksandr Andrushchenko wrote: > From: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx> > > 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. I'm kind of lost in this commit message. You are just adding a translate function in order for domUs to translate from virtual SBDF to the physical SBDF of the device. I realize you do that based on whether 'bridge' is set or not, so I assume this is just a way to signal whether the domain is a hardware domain or not. Ie: !!bridge == is_hardware_domain(v->domain). > > Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx> > --- > 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 | 18 ++++++++++++++++++ > xen/drivers/vpci/vpci.c | 27 +++++++++++++++++++++++++++ > xen/include/xen/vpci.h | 1 + > 3 files changed, 46 insertions(+) > > diff --git a/xen/arch/arm/vpci.c b/xen/arch/arm/vpci.c > index 8e801f275879..3d134f42d07e 100644 > --- a/xen/arch/arm/vpci.c > +++ b/xen/arch/arm/vpci.c > @@ -41,6 +41,15 @@ static int vpci_mmio_read(struct vcpu *v, mmio_info_t > *info, > /* data is needed to prevent a pointer cast on 32bit */ > unsigned long data; > > +#ifdef CONFIG_HAS_VPCI_GUEST_SUPPORT > + /* > + * For the passed through devices we need to map their virtual SBDF > + * to the physical PCI device being passed through. > + */ > + if ( !bridge && !vpci_translate_virtual_device(v->domain, &sbdf) ) > + return 1; I'm unsure what returning 1 implies for Arm here, but you likely need to set '*r = ~0ul;'. > +#endif > + > if ( vpci_ecam_read(sbdf, ECAM_REG_OFFSET(info->gpa), > 1U << info->dabt.size, &data) ) > { > @@ -59,6 +68,15 @@ static int vpci_mmio_write(struct vcpu *v, mmio_info_t > *info, > struct pci_host_bridge *bridge = p; > pci_sbdf_t sbdf = vpci_sbdf_from_gpa(bridge, info->gpa); > > +#ifdef CONFIG_HAS_VPCI_GUEST_SUPPORT > + /* > + * For the passed through devices we need to map their virtual SBDF > + * to the physical PCI device being passed through. > + */ > + if ( !bridge && !vpci_translate_virtual_device(v->domain, &sbdf) ) > + return 1; > +#endif > + > return vpci_ecam_write(sbdf, ECAM_REG_OFFSET(info->gpa), > 1U << info->dabt.size, r); > } > diff --git a/xen/drivers/vpci/vpci.c b/xen/drivers/vpci/vpci.c > index c2fb4d4db233..bdc8c63f73fa 100644 > --- a/xen/drivers/vpci/vpci.c > +++ b/xen/drivers/vpci/vpci.c > @@ -195,6 +195,33 @@ static void vpci_remove_virtual_device(struct domain *d, > pdev->vpci->guest_sbdf.sbdf = ~0; > } > > +/* > + * Find the physical device which is mapped to the virtual device > + * and translate virtual SBDF to the physical one. > + */ > +bool vpci_translate_virtual_device(const struct domain *d, pci_sbdf_t *sbdf) > +{ > + struct pci_dev *pdev; > + I would add: ASSERT(!is_hardware_domain(d)); To make sure this is not used for the hardware domain. > + for_each_pdev( d, pdev ) > + { > + bool found; > + > + spin_lock(&pdev->vpci_lock); > + found = pdev->vpci && (pdev->vpci->guest_sbdf.sbdf == sbdf->sbdf); > + spin_unlock(&pdev->vpci_lock); > + > + if ( found ) > + { > + /* Replace guest SBDF with the physical one. */ > + *sbdf = pdev->sbdf; > + return true; > + } > + } > + > + return false; > +} > + > /* Notify vPCI that device is assigned to guest. */ > int vpci_assign_device(struct domain *d, struct pci_dev *pdev) > { > diff --git a/xen/include/xen/vpci.h b/xen/include/xen/vpci.h > index e5258bd7ce90..21d76929391f 100644 > --- a/xen/include/xen/vpci.h > +++ b/xen/include/xen/vpci.h > @@ -280,6 +280,7 @@ static inline void vpci_cancel_pending_locked(struct > pci_dev *pdev) > /* Notify vPCI that device is assigned/de-assigned to/from guest. */ > int vpci_assign_device(struct domain *d, struct pci_dev *pdev); > int vpci_deassign_device(struct domain *d, struct pci_dev *pdev); > +bool vpci_translate_virtual_device(const struct domain *d, pci_sbdf_t *sbdf); > #else > static inline int vpci_assign_device(struct domain *d, struct pci_dev *pdev) > { If you add a dummy vpci_translate_virtual_device helper that returns false unconditionally here you could drop the #ifdefs in arm/vpci.c AFAICT. Thanks, Roger.
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