Commit 6f2d9d99 authored by Jan Beulich's avatar Jan Beulich Committed by David Vrabel

xen/acpi: allow xen-acpi-processor driver to load on Xen 4.7

As of Xen 4.7 PV CPUID doesn't expose either of CPUID[1].ECX[7] and
CPUID[0x80000007].EDX[7] anymore, causing the driver to fail to load on
both Intel and AMD systems. Doing any kind of hardware capability
checks in the driver as a prerequisite was wrong anyway: With the
hypervisor being in charge, all such checking should be done by it. If
ACPI data gets uploaded despite some missing capability, the hypervisor
is free to ignore part or all of that data.

Ditch the entire check_prereq() function, and do the only valid check
(xen_initial_domain()) in the caller in its place.
Signed-off-by: default avatarJan Beulich <>
Cc: <>
Signed-off-by: default avatarDavid Vrabel <>
parent e5a79475
......@@ -423,36 +423,7 @@ upload:
return 0;
static int __init check_prereq(void)
struct cpuinfo_x86 *c = &cpu_data(0);
if (!xen_initial_domain())
return -ENODEV;
if (!acpi_gbl_FADT.smi_command)
return -ENODEV;
if (c->x86_vendor == X86_VENDOR_INTEL) {
if (!cpu_has(c, X86_FEATURE_EST))
return -ENODEV;
return 0;
if (c->x86_vendor == X86_VENDOR_AMD) {
/* Copied from powernow-k8.h, can't include ../cpufreq/powernow
* as we get compile warnings for the static functions.
#define USE_HW_PSTATE 0x00000080
u32 eax, ebx, ecx, edx;
cpuid(CPUID_FREQ_VOLT_CAPABILITIES, &eax, &ebx, &ecx, &edx);
return -ENODEV;
return 0;
return -ENODEV;
/* acpi_perf_data is a pointer to percpu data. */
static struct acpi_processor_performance __percpu *acpi_perf_data;
......@@ -509,10 +480,10 @@ struct notifier_block xen_acpi_processor_resume_nb = {
static int __init xen_acpi_processor_init(void)
unsigned int i;
int rc = check_prereq();
int rc;
if (rc)
return rc;
if (!xen_initial_domain())
return -ENODEV;
nr_acpi_bits = get_max_acpi_id() + 1;
acpi_ids_done = kcalloc(BITS_TO_LONGS(nr_acpi_bits), sizeof(unsigned long), GFP_KERNEL);
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