[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PATCH v2 08/11] libxl: Only map legacy PCI IRQs if they are supported



On Thu, 23 Sep 2021, Oleksandr Andrushchenko wrote:
> From: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
> 
> Arm's PCI passthrough implementation doesn't support legacy interrupts,
> but MSI/MSI-X. This can be the case for other platforms too.
> For that reason introduce a new CONFIG_PCI_SUPP_LEGACY_IRQ and add
> it to the CFLAGS and compile the relevant code in the toolstack only if
> applicable.
> 
> Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
> Cc: Ian Jackson <iwj@xxxxxxxxxxxxxx>
> Cc: Juergen Gross <jgross@xxxxxxxx>
>
> ---
> Since v1:
>  - Minimized #idefery by introducing pci_supp_legacy_irq function
>    for relevant checks
> ---
>  tools/libs/light/Makefile    |  4 ++++
>  tools/libs/light/libxl_pci.c | 13 +++++++++++++
>  2 files changed, 17 insertions(+)
> 
> diff --git a/tools/libs/light/Makefile b/tools/libs/light/Makefile
> index 7d8c51d49242..bd3f6be2a183 100644
> --- a/tools/libs/light/Makefile
> +++ b/tools/libs/light/Makefile
> @@ -46,6 +46,10 @@ CFLAGS += -Wno-format-zero-length -Wmissing-declarations \
>       -Wno-declaration-after-statement -Wformat-nonliteral
>  CFLAGS += -I.
>  
> +ifeq ($(CONFIG_X86),y)
> +CFLAGS += -DCONFIG_PCI_SUPP_LEGACY_IRQ
> +endif

This patch is a lot better than the previous version, thanks!

I think the usage of pci_supp_legacy_irq below is good and we can't do
better than that.

I wonder if there is a better way than the above to export
CONFIG_PCI_SUPP_LEGACY_IRQ. Suggestions?


>  SRCS-$(CONFIG_X86) += libxl_cpuid.c
>  SRCS-$(CONFIG_X86) += libxl_x86.c
>  SRCS-$(CONFIG_X86) += libxl_psr.c
> diff --git a/tools/libs/light/libxl_pci.c b/tools/libs/light/libxl_pci.c
> index 59f3686fc85e..4c2d7aeefbb2 100644
> --- a/tools/libs/light/libxl_pci.c
> +++ b/tools/libs/light/libxl_pci.c
> @@ -1364,6 +1364,15 @@ static void pci_add_timeout(libxl__egc *egc, 
> libxl__ev_time *ev,
>      pci_add_dm_done(egc, pas, rc);
>  }
>  
> +static bool pci_supp_legacy_irq(void)
> +{
> +#ifdef CONFIG_PCI_SUPP_LEGACY_IRQ
> +    return true;
> +#else
> +    return false;
> +#endif
> +}
> +
>  static void pci_add_dm_done(libxl__egc *egc,
>                              pci_add_state *pas,
>                              int rc)
> @@ -1434,6 +1443,8 @@ static void pci_add_dm_done(libxl__egc *egc,
>          }
>      }
>      fclose(f);
> +    if (!pci_supp_legacy_irq())
> +        goto out_no_irq;
>      sysfs_path = GCSPRINTF(SYSFS_PCI_DEV"/"PCI_BDF"/irq", pci->domain,
>                                  pci->bus, pci->dev, pci->func);
>      f = fopen(sysfs_path, "r");
> @@ -1983,6 +1994,8 @@ static void do_pci_remove(libxl__egc *egc, 
> pci_remove_state *prs)
>          }
>          fclose(f);
>  skip1:
> +        if (!pci_supp_legacy_irq())
> +            goto skip_irq;
>          sysfs_path = GCSPRINTF(SYSFS_PCI_DEV"/"PCI_BDF"/irq", pci->domain,
>                                 pci->bus, pci->dev, pci->func);
>          f = fopen(sysfs_path, "r");
> -- 
> 2.25.1
> 



 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.