On 09.11.22 16:16, Roger Pau Monne wrote:
> The current logic in the Intel PMC driver will forcefully attach it
> when detecting any CPU on the intel_pmc_core_platform_ids array,
> even if the matching ACPI device is not present.
>
> There's no checking in pmc_core_probe() to assert that the PMC device
> is present, and hence on virtualized environments the PMC device
> probes successfully, even if the underlying registers are not present.
> Previous to 21ae43570940 the driver would check for the presence of a
> specific PCI device, and that prevented the driver from attaching when
> running virtualized.
>
> Fix by only forcefully attaching the PMC device when not running
> virtualized. Note that virtualized platforms can still get the device
> to load if the appropriate ACPI device is present on the tables
> provided to the VM.
>
> Make an exception for the Xen initial domain, which does have full
> hardware access, and hence can attach to the PMC if present.
>
> Fixes: 21ae43570940 ('platform/x86: intel_pmc_core: Substitute PCI with CPUID enumeration')
> Signed-off-by: Roger Pau Monné <[email protected]>
> Cc: Rajneesh Bhardwaj <[email protected]>
> Cc: David E Box <[email protected]>
> Cc: Hans de Goede <[email protected]>
> Cc: Mark Gross <[email protected]>
> Cc: Andy Shevchenko <[email protected]>
> Cc: Srinivas Pandruvada <[email protected]>
> Cc: [email protected]
> ---
> drivers/platform/x86/intel/pmc/pltdrv.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/drivers/platform/x86/intel/pmc/pltdrv.c b/drivers/platform/x86/intel/pmc/pltdrv.c
> index 15ca8afdd973..e284fd34ffdf 100644
> --- a/drivers/platform/x86/intel/pmc/pltdrv.c
> +++ b/drivers/platform/x86/intel/pmc/pltdrv.c
> @@ -18,6 +18,8 @@
> #include <asm/cpu_device_id.h>
> #include <asm/intel-family.h>
>
> +#include <xen/xen.h>
> +
> static void intel_pmc_core_release(struct device *dev)
> {
> kfree(dev);
> @@ -53,6 +55,14 @@ static int __init pmc_core_platform_init(void)
> if (acpi_dev_present("INT33A1", NULL, -1))
> return -ENODEV;
>
> + /*
> + * Skip forcefully attaching the device for VMs. Make an exception for
> + * Xen dom0, which does have full hardware access.
> + */
> + if (boot_cpu_has(X86_FEATURE_HYPERVISOR) &&
Please use cpu_feature_enabled() instead of boot_cpu_has().
Juergen