4  * cpuid support routines
24 #include <asm/cpuid.h>
25 #include "cpuid.h"
85  * Magic value used by KVM when querying userspace-provided CPUID entries and
89  * to avoid false positives when processing guest CPUID input.
100 	 * KVM has a semi-arbitrary rule that querying the guest's CPUID model  in cpuid_entry2_find()
101 	 * with IRQs disabled is disallowed.  The CPUID model can legitimately  in cpuid_entry2_find()
107 	 * of the hotpath, e.g. by caching information during CPUID updates.  in cpuid_entry2_find()
128 		 * 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
400 	 * Reset guest capabilities to userspace's guest CPUID definition, i.e.  in kvm_vcpu_after_set_cpuid()
405 		const struct cpuid_reg cpuid = reverse_cpuid[i];  in kvm_vcpu_after_set_cpuid()  local
408 		if (!cpuid.function)  in kvm_vcpu_after_set_cpuid()
411 		entry = kvm_find_cpuid_entry_index(vcpu, cpuid.function, cpuid.index);  in kvm_vcpu_after_set_cpuid()
415 		cpuid_func_emulated(&emulated, cpuid.function, true);  in kvm_vcpu_after_set_cpuid()
419 		 * in guest CPUID.  Note, this includes features that are  in kvm_vcpu_after_set_cpuid()
423 					 cpuid_get_reg_unsafe(&emulated, cpuid.reg);  in kvm_vcpu_after_set_cpuid()
424 		vcpu->arch.cpu_caps[i] &= cpuid_get_reg_unsafe(entry, cpuid.reg);  in kvm_vcpu_after_set_cpuid()
437 	 * If TDP is disabled, honor *only* guest CPUID as KVM has full control  in kvm_vcpu_after_set_cpuid()
514 	 * that KVM controls, without clobbering the current guest CPUID, which  in kvm_set_cpuid()
518 	 * can be updated alongside the CPUID entries when performing runtime  in kvm_set_cpuid()
520 	 * run, i.e. only if userspace is potentially changing CPUID features.  in kvm_set_cpuid()
529 	 * KVM does not correctly handle changing guest CPUID after KVM_RUN, as  in kvm_set_cpuid()
537 	 * whether the supplied CPUID data is equal to what's already set.  in kvm_set_cpuid()
559 	vcpu->arch.xen.cpuid = kvm_get_hypervisor_cpuid(vcpu, XEN_SIGNATURE);  in kvm_set_cpuid()
576 			     struct kvm_cpuid *cpuid,  in kvm_vcpu_ioctl_set_cpuid()  argument
583 	if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)  in kvm_vcpu_ioctl_set_cpuid()
586 	if (cpuid->nent) {  in kvm_vcpu_ioctl_set_cpuid()
587 		e = vmemdup_array_user(entries, cpuid->nent, sizeof(*e));  in kvm_vcpu_ioctl_set_cpuid()
591 		e2 = kvmalloc_array(cpuid->nent, sizeof(*e2), GFP_KERNEL_ACCOUNT);  in kvm_vcpu_ioctl_set_cpuid()
597 	for (i = 0; i < cpuid->nent; i++) {  in kvm_vcpu_ioctl_set_cpuid()
610 	r = kvm_set_cpuid(vcpu, e2, cpuid->nent);  in kvm_vcpu_ioctl_set_cpuid()
621 			      struct kvm_cpuid2 *cpuid,  in kvm_vcpu_ioctl_set_cpuid2()  argument
627 	if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)  in kvm_vcpu_ioctl_set_cpuid2()
630 	if (cpuid->nent) {  in kvm_vcpu_ioctl_set_cpuid2()
631 		e2 = vmemdup_array_user(entries, cpuid->nent, sizeof(*e2));  in kvm_vcpu_ioctl_set_cpuid2()
636 	r = kvm_set_cpuid(vcpu, e2, cpuid->nent);  in kvm_vcpu_ioctl_set_cpuid2()
644 			      struct kvm_cpuid2 *cpuid,  in kvm_vcpu_ioctl_get_cpuid2()  argument
647 	if (cpuid->nent < vcpu->arch.cpuid_nent)  in kvm_vcpu_ioctl_get_cpuid2()
657 	cpuid->nent = vcpu->arch.cpuid_nent;  in kvm_vcpu_ioctl_get_cpuid2()
661 static __always_inline u32 raw_cpuid_get(struct cpuid_reg cpuid)  in raw_cpuid_get()  argument
671 	base = cpuid.function & 0xffff0000;  in raw_cpuid_get()
675 	if (cpuid_eax(base) < cpuid.function)  in raw_cpuid_get()
678 	cpuid_count(cpuid.function, cpuid.index,  in raw_cpuid_get()
681 	return *__cpuid_entry_get_reg(&entry, cpuid.reg);  in raw_cpuid_get()
686  * capabilities as well as raw CPUID.  For KVM-defined leafs, consult only raw
687  * CPUID, as KVM is the one and only authority (in the kernel).
691 	const struct cpuid_reg cpuid = x86_feature_cpuid(leaf * 32);	\
707 	kvm_cpu_caps[leaf] &= (raw_cpuid_get(cpuid) |			\
713  * Assert that the feature bit being declared, e.g. via F(), is in the CPUID
759  * i.e. may not be present in the raw CPUID, but can still be advertised to
770  * hardware CPUID, i.e. that KVM virtualizes even if the host kernel doesn't
772  * CPUID support will be factored in by kvm_cpu_cap_mask().
831 		 * advertised to guests via CPUID!  MWAIT is also technically a  in kvm_set_cpu_caps()
1169 		 * in KVM's supported CPUID, i.e. if the feature is reported as  in kvm_set_cpu_caps()
1174 		 * CPUID will drop the flags, and reporting support in AMD's  in kvm_set_cpu_caps()
1366 		 * CPUID(function=2, index=0) may return different results each  in __do_cpuid_func()
1368 		 * number of times software should do CPUID(2, 0).  in __do_cpuid_func()
1374 		 * APM states that CPUID(2) is reserved.  in __do_cpuid_func()
1377 		 * a stateful CPUID.0x2 is encountered.  in __do_cpuid_func()
1636 		 * NullSegClearsBase is not reported in CPUID on Zen2; help  in __do_cpuid_func()
1637 		 * userspace by providing the CPUID leaf ourselves.  in __do_cpuid_func()
1639 		 * However, only do it if the host has CPUID leaf 0x8000001d.  in __do_cpuid_func()
1641 		 * CPUID leaf if KVM reports that it supports 0x8000001d or  in __do_cpuid_func()
1778 	/*Add support for Centaur's CPUID instruction*/  in __do_cpuid_func()
1866 int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,  in kvm_dev_ioctl_get_cpuid()  argument
1879 	if (cpuid->nent < 1)  in kvm_dev_ioctl_get_cpuid()
1881 	if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)  in kvm_dev_ioctl_get_cpuid()
1882 		cpuid->nent = KVM_MAX_CPUID_ENTRIES;  in kvm_dev_ioctl_get_cpuid()
1884 	if (sanity_check_entries(entries, cpuid->nent, type))  in kvm_dev_ioctl_get_cpuid()
1887 	array.entries = kvcalloc(cpuid->nent, sizeof(struct kvm_cpuid_entry2), GFP_KERNEL);  in kvm_dev_ioctl_get_cpuid()
1891 	array.maxnent = cpuid->nent;  in kvm_dev_ioctl_get_cpuid()
1898 	cpuid->nent = array.nent;  in kvm_dev_ioctl_get_cpuid()
1910  * Intel CPUID semantics treats any query for an out-of-range leaf as if the
1911  * highest basic leaf (i.e. CPUID.0H:EAX) were requested.  AMD CPUID semantics
1921  * class exists if a guest CPUID entry for its <base> leaf exists.  For a given
1922  * class, CPUID.<base>.EAX contains the max supported leaf for the class.
1932  * CPUID sub-classes are:
1964 	 * entry for CPUID.0xb.index (see below), then the output value for EDX  in get_out_of_range_cpuid_entry()
1965 	 * needs to be pulled from CPUID.0xb.1.  in get_out_of_range_cpuid_entry()
1971 	 * the effective CPUID entry is the max basic leaf.  Note, the index of  in get_out_of_range_cpuid_entry()