On Wed, Oct 06, 2021 at 06:40:34PM +0100, Rahul Singh wrote:
> The existing VPCI support available for X86 is adapted for Arm.
> When the device is added to XEN via the hyper call
> “PHYSDEVOP_pci_device_add”, VPCI handler for the config space
> access is added to the Xen to emulate the PCI devices config space.
>
> A MMIO trap handler for the PCI ECAM space is registered in XEN
> so that when guest is trying to access the PCI config space,XEN
> will trap the access and emulate read/write using the VPCI and
> not the real PCI hardware.
>
> For Dom0less systems scan_pci_devices() would be used to discover the
> PCI device in XEN and VPCI handler will be added during XEN boots.
>
> Signed-off-by: Rahul Singh <rahul.si...@arm.com>
> Reviewed-by: Stefano Stabellini <sstabell...@kernel.org>
> ---
> Change in v5:
> - Add pci_cleanup_msi(pdev) in cleanup part.
> - Added Reviewed-by: Stefano Stabellini <sstabell...@kernel.org>
> Change in v4:
> - Move addition of XEN_DOMCTL_CDF_vpci flag to separate patch
> Change in v3:
> - Use is_pci_passthrough_enabled() in place of pci_passthrough_enabled
> variable
> - Reject XEN_DOMCTL_CDF_vpci for x86 in arch_sanitise_domain_config()
> - Remove IS_ENABLED(CONFIG_HAS_VPCI) from has_vpci()
> Change in v2:
> - Add new XEN_DOMCTL_CDF_vpci flag
> - modify has_vpci() to include XEN_DOMCTL_CDF_vpci
> - enable vpci support when pci-passthough option is enabled.
> ---
> ---
> xen/arch/arm/Makefile | 1 +
> xen/arch/arm/domain.c | 4 ++
> xen/arch/arm/domain_build.c | 3 +
> xen/arch/arm/vpci.c | 102 ++++++++++++++++++++++++++++++++++
> xen/arch/arm/vpci.h | 36 ++++++++++++
> xen/drivers/passthrough/pci.c | 18 ++++++
> xen/include/asm-arm/domain.h | 7 ++-
> xen/include/asm-x86/pci.h | 2 -
> xen/include/public/arch-arm.h | 7 +++
> xen/include/xen/pci.h | 2 +
> 10 files changed, 179 insertions(+), 3 deletions(-)
> create mode 100644 xen/arch/arm/vpci.c
> create mode 100644 xen/arch/arm/vpci.h
>
> diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
> index 44d7cc81fa..fb9c976ea2 100644
> --- a/xen/arch/arm/Makefile
> +++ b/xen/arch/arm/Makefile
> @@ -7,6 +7,7 @@ ifneq ($(CONFIG_NO_PLAT),y)
> obj-y += platforms/
> endif
> obj-$(CONFIG_TEE) += tee/
> +obj-$(CONFIG_HAS_VPCI) += vpci.o
>
> obj-$(CONFIG_HAS_ALTERNATIVE) += alternative.o
> obj-y += bootfdt.init.o
> diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
> index 36138c1b2e..fbb52f78f1 100644
> --- a/xen/arch/arm/domain.c
> +++ b/xen/arch/arm/domain.c
> @@ -39,6 +39,7 @@
> #include <asm/vgic.h>
> #include <asm/vtimer.h>
>
> +#include "vpci.h"
> #include "vuart.h"
>
> DEFINE_PER_CPU(struct vcpu *, curr_vcpu);
> @@ -767,6 +768,9 @@ int arch_domain_create(struct domain *d,
> if ( is_hardware_domain(d) && (rc = domain_vuart_init(d)) )
> goto fail;
>
> + if ( (rc = domain_vpci_init(d)) != 0 )
> + goto fail;
> +
> return 0;
>
> fail:
> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> index c5afbe2e05..f4c89bde8c 100644
> --- a/xen/arch/arm/domain_build.c
> +++ b/xen/arch/arm/domain_build.c
> @@ -3053,6 +3053,9 @@ void __init create_dom0(void)
> if ( iommu_enabled )
> dom0_cfg.flags |= XEN_DOMCTL_CDF_iommu;
>
> + if ( is_pci_passthrough_enabled() )
> + dom0_cfg.flags |= XEN_DOMCTL_CDF_vpci;
I think I'm confused with this. You seem to enable vPCI for dom0, but
then domain_vpci_init will setup traps for the guest virtual ECAM
layout, not the native one that dom0 will be using.
> +
> dom0 = domain_create(0, &dom0_cfg, true);
> if ( IS_ERR(dom0) || (alloc_dom0_vcpu0(dom0) == NULL) )
> panic("Error creating domain 0\n");
> diff --git a/xen/arch/arm/vpci.c b/xen/arch/arm/vpci.c
> new file mode 100644
> index 0000000000..76c12b9281
> --- /dev/null
> +++ b/xen/arch/arm/vpci.c
> @@ -0,0 +1,102 @@
> +/*
> + * 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 <asm/mmio.h>
> +
> +#define REGISTER_OFFSET(addr) ( (addr) & 0x00000fff)
> +
> +/* Do some sanity checks. */
> +static bool vpci_mmio_access_allowed(unsigned int reg, unsigned int len)
> +{
> + /* Check access size. */
> + if ( len > 8 )
> + return false;
> +
> + /* Check that access is size aligned. */
> + if ( (reg & (len - 1)) )
> + return false;
> +
> + return true;
> +}
There's a vpci_access_allowed which I think you could generalize and
use here, there's no need to have this duplicated code.
Thanks, Roger.
