From: Roger Pau Monné roger.pau@citrix.com
[ Upstream commit 2dbfb3f33350e1e868d3d7ed4c176d8777150878 ]
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. Before commit 21ae43570940 ("platform/x86: intel_pmc_core: Substitute PCI with CPUID enumeration") 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 roger.pau@citrix.com Acked-by: David E. Box david.e.box@linux.intel.com Reviewed-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Link: https://lore.kernel.org/r/20221110163145.80374-1-roger.pau@citrix.com Reviewed-by: Hans de Goede hdegoede@redhat.com Signed-off-by: Hans de Goede hdegoede@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/platform/x86/intel_pmc_core_pltdrv.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/drivers/platform/x86/intel_pmc_core_pltdrv.c b/drivers/platform/x86/intel_pmc_core_pltdrv.c index 15ca8afdd973..ddfba38c2104 100644 --- a/drivers/platform/x86/intel_pmc_core_pltdrv.c +++ b/drivers/platform/x86/intel_pmc_core_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 +55,13 @@ 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 (cpu_feature_enabled(X86_FEATURE_HYPERVISOR) && !xen_initial_domain()) + return -ENODEV; + if (!x86_match_cpu(intel_pmc_core_platform_ids)) return -ENODEV;