Ping?
So far I've got some feedback from Jan which I've replied to, but I
haven't got any more feedback.
Both patches 1 and 2 are required in order for Xen dom0s to properly
handle ACPI Processor related data to the hypervisor. Patch 3 can be
deal with later.
Thanks, Roger.
On Mon, Nov 21, 2022 at 11:21:10AM +0100, Roger Pau Monne wrote:
> When running as a Xen dom0 the number of CPUs available to Linux can
> be different from the number of CPUs present on the system, but in
> order to properly fetch processor performance related data _PDC must
> be executed on all the physical CPUs online on the system.
>
> The current checks in processor_physically_present() result in some
> processor objects not getting their _PDC methods evaluated when Linux
> is running as Xen dom0. Fix this by introducing a custom function to
> use when running as Xen dom0 in order to check whether a processor
> object matches a CPU that's online.
>
> Fixes: 5d554a7bb064 ('ACPI: processor: add internal
> processor_physically_present()')
> Signed-off-by: Roger Pau Monné <roger....@citrix.com>
> ---
> arch/x86/include/asm/xen/hypervisor.h | 10 ++++++++++
> arch/x86/xen/enlighten.c | 27 +++++++++++++++++++++++++++
> drivers/acpi/processor_pdc.c | 11 +++++++++++
> 3 files changed, 48 insertions(+)
>
> diff --git a/arch/x86/include/asm/xen/hypervisor.h
> b/arch/x86/include/asm/xen/hypervisor.h
> index 16f548a661cf..b9f512138043 100644
> --- a/arch/x86/include/asm/xen/hypervisor.h
> +++ b/arch/x86/include/asm/xen/hypervisor.h
> @@ -61,4 +61,14 @@ void __init xen_pvh_init(struct boot_params *boot_params);
> void __init mem_map_via_hcall(struct boot_params *boot_params_p);
> #endif
>
> +#ifdef CONFIG_XEN_DOM0
> +bool __init xen_processor_present(uint32_t acpi_id);
> +#else
> +static inline bool xen_processor_present(uint32_t acpi_id)
> +{
> + BUG();
> + return false;
> +}
> +#endif
> +
> #endif /* _ASM_X86_XEN_HYPERVISOR_H */
> diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
> index b8db2148c07d..d4c44361a26c 100644
> --- a/arch/x86/xen/enlighten.c
> +++ b/arch/x86/xen/enlighten.c
> @@ -346,3 +346,30 @@ void xen_arch_unregister_cpu(int num)
> }
> EXPORT_SYMBOL(xen_arch_unregister_cpu);
> #endif
> +
> +#ifdef CONFIG_XEN_DOM0
> +bool __init xen_processor_present(uint32_t acpi_id)
> +{
> + unsigned int i, maxid;
> + struct xen_platform_op op = {
> + .cmd = XENPF_get_cpuinfo,
> + .interface_version = XENPF_INTERFACE_VERSION,
> + };
> + int ret = HYPERVISOR_platform_op(&op);
> +
> + if (ret)
> + return false;
> +
> + maxid = op.u.pcpu_info.max_present;
> + for (i = 0; i <= maxid; i++) {
> + op.u.pcpu_info.xen_cpuid = i;
> + ret = HYPERVISOR_platform_op(&op);
> + if (ret)
> + continue;
> + if (op.u.pcpu_info.acpi_id == acpi_id)
> + return op.u.pcpu_info.flags & XEN_PCPU_FLAGS_ONLINE;
> + }
> +
> + return false;
> +}
> +#endif
> diff --git a/drivers/acpi/processor_pdc.c b/drivers/acpi/processor_pdc.c
> index 8c3f82c9fff3..18fb04523f93 100644
> --- a/drivers/acpi/processor_pdc.c
> +++ b/drivers/acpi/processor_pdc.c
> @@ -14,6 +14,8 @@
> #include <linux/acpi.h>
> #include <acpi/processor.h>
>
> +#include <xen/xen.h>
> +
> #include "internal.h"
>
> static bool __init processor_physically_present(acpi_handle handle)
> @@ -47,6 +49,15 @@ static bool __init
> processor_physically_present(acpi_handle handle)
> return false;
> }
>
> + if (xen_initial_domain())
> + /*
> + * When running as a Xen dom0 the number of processors Linux
> + * sees can be different from the real number of processors on
> + * the system, and we still need to execute _PDC for all of
> + * them.
> + */
> + return xen_processor_present(acpi_id);
> +
> type = (acpi_type == ACPI_TYPE_DEVICE) ? 1 : 0;
> cpuid = acpi_get_cpuid(handle, type, acpi_id);
>
> --
> 2.37.3
>
