Commit 6eac4d99 authored by Sean Christopherson's avatar Sean Christopherson
Browse files

KVM: x86: Add a macro to init CPUID features that are 64-bit only 



Add a macro to mask-in feature flags that are supported only on 64-bit
kernels/KVM.  In addition to reducing overall #ifdeffery, using a macro
will allow hardening the kvm_cpu_cap initialization sequences to assert
that the features being advertised are indeed included in the word being
initialized.  And arguably using *F() macros through is more readable.

No functional change intended.

Reviewed-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: default avatarXiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20241128013424.4096668-25-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 3cc359ca

arch/x86/kvm/cpuid.c

+10 −12
Original line number Diff line number Diff line
@@ -663,17 +663,14 @@ static __always_inline void kvm_cpu_cap_init(enum cpuid_leafs leaf, u32 mask) 
	(boot_cpu_has(X86_FEATURE_##name) ? F(name) : 0);	\

})



/* Features that KVM supports only on 64-bit kernels. */

#define X86_64_F(name)						\

({								\

	(IS_ENABLED(CONFIG_X86_64) ? F(name) : 0);		\

})



void kvm_set_cpu_caps(void)

{

#ifdef CONFIG_X86_64

	unsigned int f_gbpages = F(GBPAGES);

	unsigned int f_lm = F(LM);

	unsigned int f_xfd = F(XFD);

#else

	unsigned int f_gbpages = 0;

	unsigned int f_lm = 0;

	unsigned int f_xfd = 0;

#endif

	memset(kvm_cpu_caps, 0, sizeof(kvm_cpu_caps));



	BUILD_BUG_ON(sizeof(kvm_cpu_caps) - (NKVMCAPINTS * sizeof(*kvm_cpu_caps)) >
@@ -880,7 +877,7 @@ void kvm_set_cpu_caps(void) 
		F(XSAVEC) |

		F(XGETBV1) |

		F(XSAVES) |

		f_xfd

		X86_64_F(XFD)

	);



	kvm_cpu_cap_init_kvm_defined(CPUID_12_EAX,
@@ -941,10 +938,10 @@ void kvm_set_cpu_caps(void) 
		F(MMX) |

		F(FXSR) |

		F(FXSR_OPT) |

		f_gbpages |

		X86_64_F(GBPAGES) |

		F(RDTSCP) |

		0 /* Reserved */ |

		f_lm |

		X86_64_F(LM) |

		F(3DNOWEXT) |

		F(3DNOW)

	);
@@ -1078,6 +1075,7 @@ EXPORT_SYMBOL_GPL(kvm_set_cpu_caps); 


#undef F

#undef SF

#undef X86_64_F



struct kvm_cpuid_array {

	struct kvm_cpuid_entry2 *entries;