On 18.10.21 17:19, Jan Beulich wrote: > On 18.10.2021 16:07, Oleksandr Andrushchenko wrote: >> On 18.10.21 13:29, Jan Beulich wrote: >>> On 18.10.2021 12:11, Bertrand Marquis wrote: >>>>> On 18 Oct 2021, at 08:47, Jan Beulich <[email protected]> wrote: >>>>> On 15.10.2021 18:51, Bertrand Marquis wrote: >>>>>> --- /dev/null >>>>>> +++ b/xen/arch/arm/vpci.c >>>>>> @@ -0,0 +1,77 @@ >>>>>> +/* >>>>>> + * xen/arch/arm/vpci.c >>>>>> + * >>>>>> + * This program is free software; you can redistribute it and/or modify >>>>>> + * it under the terms of the GNU General Public License as published by >>>>>> + * the Free Software Foundation; either version 2 of the License, or >>>>>> + * (at your option) any later version. >>>>>> + * >>>>>> + * This program is distributed in the hope that it will be useful, >>>>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of >>>>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the >>>>>> + * GNU General Public License for more details. >>>>>> + */ >>>>>> +#include <xen/sched.h> >>>>>> +#include <xen/vpci.h> >>>>>> + >>>>>> +#include <asm/mmio.h> >>>>>> + >>>>>> +static int vpci_mmio_read(struct vcpu *v, mmio_info_t *info, >>>>>> + register_t *r, void *p) >>>>>> +{ >>>>>> + pci_sbdf_t sbdf; >>>>>> + /* data is needed to prevent a pointer cast on 32bit */ >>>>>> + unsigned long data; >>>>>> + >>>>>> + /* We ignore segment part and always handle segment 0 */ >>>>>> + sbdf.sbdf = VPCI_ECAM_BDF(info->gpa); >>>>>> + >>>>>> + if ( vpci_ecam_read(sbdf, ECAM_REG_OFFSET(info->gpa), >>>>>> + 1U << info->dabt.size, &data) ) >>>>>> + { >>>>> Here it is quite clear that the SBDF you pass into vpci_ecam_read() is >>>>> the virtual one. The function then calls vpci_read(), which in turn >>>>> will call vpci_read_hw() in a number of situations (first and foremost >>>>> whenever pci_get_pdev_by_domain() returns NULL). That function as well >>>>> as pci_get_pdev_by_domain() use the passed in SBDF as if it was a >>>>> physical one; I'm unable to spot any translation. Yet I do recall >>>>> seeing assignment of a virtual device and function number somewhere >>>>> (perhaps another of the related series), so the model also doesn't >>>>> look to assume 1:1 mapping of SBDF. >>>> This question was answered by Oleksandr I think. >>> Yes; I continue to be sure though that I saw devfn allocation logic in >>> one of the many patches that are related here. And I'm relatively sure >>> that there no adjustment to logic here was made (but since it's hard >>> to pick the right patch out of the huge pile without knowing its title, >>> I can't reasonably go check). >> Offtop: I was somehow dropped from the Cc.. >> >> Please see: >> >> [PATCH v3 10/11] vpci: Add initial support for virtual PCI bus topology >> [PATCH v3 11/11] xen/arm: Translate virtual PCI bus topology for guests >> >> [1] >> https://urldefense.com/v3/__https://patchwork.kernel.org/project/xen-devel/list/?series=555481__;!!GF_29dbcQIUBPA!mM8A39p8nk4UMK3YeKMMW9ua9BHj1UOWzaQcyx7G46YPdudxMpD3huqZfih0Uc8S-GyWXD_mPg$ >> [patchwork[.]kernel[.]org] > Ah yes, this way I can find them in my mailbox. And indeed - no translation > from virtual to physical SBDF on the config space read/write paths afaics. There are translations for both read and write [2] such as:
+ /* + * For the passed through devices we need to map their virtual SBDF + * to the physical PCI device being passed through. + */ + if ( priv->is_virt_ecam && !pci_translate_virtual_device(v->domain, &sbdf) ) + return 1; + > > Thanks for the pointer, > Jan > [2] https://patchwork.kernel.org/project/xen-devel/patch/[email protected]/
