4  * cpuid support routines
24 #include <asm/cpuid.h>
25 #include "cpuid.h"
86  * Magic value used by KVM when querying userspace-provided CPUID entries and
90  * to avoid false positives when processing guest CPUID input.
101 	 * KVM has a semi-arbitrary rule that querying the guest's CPUID model  in cpuid_entry2_find()
102 	 * with IRQs disabled is disallowed.  The CPUID model can legitimately  in cpuid_entry2_find()
108 	 * of the hotpath, e.g. by caching information during CPUID updates.  in cpuid_entry2_find()
129 		 * lookup (as opposed to emulating CPUID) for a function that's  in cpuid_entry2_find()
200 /* Check whether the supplied CPUID data is equal to what is already set for the vCPU. */
208 	 * Apply runtime CPUID updates to the incoming CPUID entries to avoid  in kvm_cpuid_check_equal()
211 	 * Note!  @e2 and @nent track the _old_ CPUID entries!  in kvm_cpuid_check_equal()
235 	struct kvm_hypervisor_cpuid cpuid = {};  in kvm_get_hypervisor_cpuid()  local
250 				cpuid.base = base;  in kvm_get_hypervisor_cpuid()
251 				cpuid.limit = entry->eax;  in kvm_get_hypervisor_cpuid()
257 	return cpuid;  in kvm_get_hypervisor_cpuid()
280  * Calculate guest's supported XCR0 taking into account guest CPUID data and
399 	 * Reset guest capabilities to userspace's guest CPUID definition, i.e.  in kvm_vcpu_after_set_cpuid()
404 		const struct cpuid_reg cpuid = reverse_cpuid[i];  in kvm_vcpu_after_set_cpuid()  local
407 		if (!cpuid.function)  in kvm_vcpu_after_set_cpuid()
410 		entry = kvm_find_cpuid_entry_index(vcpu, cpuid.function, cpuid.index);  in kvm_vcpu_after_set_cpuid()
414 		cpuid_func_emulated(&emulated, cpuid.function, true);  in kvm_vcpu_after_set_cpuid()
418 		 * in guest CPUID.  Note, this includes features that are  in kvm_vcpu_after_set_cpuid()
422 					 cpuid_get_reg_unsafe(&emulated, cpuid.reg);  in kvm_vcpu_after_set_cpuid()
423 		vcpu->arch.cpu_caps[i] &= cpuid_get_reg_unsafe(entry, cpuid.reg);  in kvm_vcpu_after_set_cpuid()
436 	 * If TDP is disabled, honor *only* guest CPUID as KVM has full control  in kvm_vcpu_after_set_cpuid()
513 	 * that KVM controls, without clobbering the current guest CPUID, which  in kvm_set_cpuid()
517 	 * can be updated alongside the CPUID entries when performing runtime  in kvm_set_cpuid()
519 	 * run, i.e. only if userspace is potentially changing CPUID features.  in kvm_set_cpuid()
528 	 * KVM does not correctly handle changing guest CPUID after KVM_RUN, as  in kvm_set_cpuid()
536 	 * whether the supplied CPUID data is equal to what's already set.  in kvm_set_cpuid()
558 	vcpu->arch.xen.cpuid = kvm_get_hypervisor_cpuid(vcpu, XEN_SIGNATURE);  in kvm_set_cpuid()
575 			     struct kvm_cpuid *cpuid,  in kvm_vcpu_ioctl_set_cpuid()  argument
582 	if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)  in kvm_vcpu_ioctl_set_cpuid()
585 	if (cpuid->nent) {  in kvm_vcpu_ioctl_set_cpuid()
586 		e = vmemdup_array_user(entries, cpuid->nent, sizeof(*e));  in kvm_vcpu_ioctl_set_cpuid()
590 		e2 = kvmalloc_array(cpuid->nent, sizeof(*e2), GFP_KERNEL_ACCOUNT);  in kvm_vcpu_ioctl_set_cpuid()
596 	for (i = 0; i < cpuid->nent; i++) {  in kvm_vcpu_ioctl_set_cpuid()
609 	r = kvm_set_cpuid(vcpu, e2, cpuid->nent);  in kvm_vcpu_ioctl_set_cpuid()
620 			      struct kvm_cpuid2 *cpuid,  in kvm_vcpu_ioctl_set_cpuid2()  argument
626 	if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)  in kvm_vcpu_ioctl_set_cpuid2()
629 	if (cpuid->nent) {  in kvm_vcpu_ioctl_set_cpuid2()
630 		e2 = vmemdup_array_user(entries, cpuid->nent, sizeof(*e2));  in kvm_vcpu_ioctl_set_cpuid2()
635 	r = kvm_set_cpuid(vcpu, e2, cpuid->nent);  in kvm_vcpu_ioctl_set_cpuid2()
643 			      struct kvm_cpuid2 *cpuid,  in kvm_vcpu_ioctl_get_cpuid2()  argument
646 	if (cpuid->nent < vcpu->arch.cpuid_nent)  in kvm_vcpu_ioctl_get_cpuid2()
653 	cpuid->nent = vcpu->arch.cpuid_nent;  in kvm_vcpu_ioctl_get_cpuid2()
657 static __always_inline u32 raw_cpuid_get(struct cpuid_reg cpuid)  in raw_cpuid_get()  argument
667 	base = cpuid.function & 0xffff0000;  in raw_cpuid_get()
671 	if (cpuid_eax(base) < cpuid.function)  in raw_cpuid_get()
674 	cpuid_count(cpuid.function, cpuid.index,  in raw_cpuid_get()
677 	return *__cpuid_entry_get_reg(&entry, cpuid.reg);  in raw_cpuid_get()
682  * capabilities as well as raw CPUID.  For KVM-defined leafs, consult only raw
683  * CPUID, as KVM is the one and only authority (in the kernel).
687 	const struct cpuid_reg cpuid = x86_feature_cpuid(leaf * 32);	\
703 	kvm_cpu_caps[leaf] &= (raw_cpuid_get(cpuid) |			\
709  * Assert that the feature bit being declared, e.g. via F(), is in the CPUID
755  * i.e. may not be present in the raw CPUID, but can still be advertised to
766  * hardware CPUID, i.e. that KVM virtualizes even if the host kernel doesn't
768  * CPUID support will be factored in by kvm_cpu_cap_mask().
827 		 * advertised to guests via CPUID!  MWAIT is also technically a  in kvm_set_cpu_caps()
1165 		 * in KVM's supported CPUID, i.e. if the feature is reported as  in kvm_set_cpu_caps()
1170 		 * CPUID will drop the flags, and reporting support in AMD's  in kvm_set_cpu_caps()
1362 		 * CPUID(function=2, index=0) may return different results each  in __do_cpuid_func()
1364 		 * number of times software should do CPUID(2, 0).  in __do_cpuid_func()
1370 		 * APM states that CPUID(2) is reserved.  in __do_cpuid_func()
1373 		 * a stateful CPUID.0x2 is encountered.  in __do_cpuid_func()
1632 		 * NullSegClearsBase is not reported in CPUID on Zen2; help  in __do_cpuid_func()
1633 		 * userspace by providing the CPUID leaf ourselves.  in __do_cpuid_func()
1635 		 * However, only do it if the host has CPUID leaf 0x8000001d.  in __do_cpuid_func()
1637 		 * CPUID leaf if KVM reports that it supports 0x8000001d or  in __do_cpuid_func()
1780 	/*Add support for Centaur's CPUID instruction*/  in __do_cpuid_func()
1868 int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,  in kvm_dev_ioctl_get_cpuid()  argument
1881 	if (cpuid->nent < 1)  in kvm_dev_ioctl_get_cpuid()
1883 	if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)  in kvm_dev_ioctl_get_cpuid()
1884 		cpuid->nent = KVM_MAX_CPUID_ENTRIES;  in kvm_dev_ioctl_get_cpuid()
1886 	if (sanity_check_entries(entries, cpuid->nent, type))  in kvm_dev_ioctl_get_cpuid()
1889 	array.entries = kvcalloc(cpuid->nent, sizeof(struct kvm_cpuid_entry2), GFP_KERNEL);  in kvm_dev_ioctl_get_cpuid()
1893 	array.maxnent = cpuid->nent;  in kvm_dev_ioctl_get_cpuid()
1900 	cpuid->nent = array.nent;  in kvm_dev_ioctl_get_cpuid()
1912  * Intel CPUID semantics treats any query for an out-of-range leaf as if the
1913  * highest basic leaf (i.e. CPUID.0H:EAX) were requested.  AMD CPUID semantics
1923  * class exists if a guest CPUID entry for its <base> leaf exists.  For a given
1924  * class, CPUID.<base>.EAX contains the max supported leaf for the class.
1934  * CPUID sub-classes are:
1966 	 * entry for CPUID.0xb.index (see below), then the output value for EDX  in get_out_of_range_cpuid_entry()
1967 	 * needs to be pulled from CPUID.0xb.1.  in get_out_of_range_cpuid_entry()
1973 	 * the effective CPUID entry is the max basic leaf.  Note, the index of  in get_out_of_range_cpuid_entry()