Commit 5d0316e2 authored by Naveen N Rao's avatar Naveen N Rao Committed by Sean Christopherson
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x86/cpufeatures: Add X86_FEATURE_X2AVIC_EXT 



Add CPUID feature bit for x2AVIC extension that enables AMD SVM to
support up to 4096 vCPUs in x2AVIC mode. The primary change is in the
size of the AVIC Physical ID table, which can now go up to 8 contiguous
4k pages. The number of pages allocated is controlled by the maximum
APIC ID for a guest, and that controls the number of pages to allocate
for the AVIC Physical ID table. AVIC hardware is enhanced to look up
Physical ID table entries for vCPUs > 512 for locating the target APIC
backing page and the host APIC ID of the physical core on which the
guest vCPU is running.

Signed-off-by: default avatarNaveen N Rao (AMD) <naveen@kernel.org>
Acked-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/e5c9c471ab99a130bf9b728b77050ab308cf8624.1757009416.git.naveen@kernel.org


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 54ffe74c

arch/x86/include/asm/cpufeatures.h

+1 −0
Original line number Diff line number Diff line
@@ -500,6 +500,7 @@ 
#define X86_FEATURE_IBPB_EXIT_TO_USER	(21*32+14) /* Use IBPB on exit-to-userspace, see VMSCAPE bug */

#define X86_FEATURE_ABMC		(21*32+15) /* Assignable Bandwidth Monitoring Counters */

#define X86_FEATURE_MSR_IMM		(21*32+16) /* MSR immediate form instructions */

#define X86_FEATURE_X2AVIC_EXT		(21*32+17) /* AMD SVM x2AVIC support for 4k vCPUs */



/*

 * BUG word(s)

arch/x86/kernel/cpu/scattered.c

+1 −0
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ static const struct cpuid_bit cpuid_bits[] = { 
	{ X86_FEATURE_PROC_FEEDBACK,		CPUID_EDX, 11, 0x80000007, 0 },

	{ X86_FEATURE_AMD_FAST_CPPC,		CPUID_EDX, 15, 0x80000007, 0 },

	{ X86_FEATURE_MBA,			CPUID_EBX,  6, 0x80000008, 0 },

	{ X86_FEATURE_X2AVIC_EXT,		CPUID_ECX,  6, 0x8000000a, 0 },

	{ X86_FEATURE_COHERENCY_SFW_NO,		CPUID_EBX, 31, 0x8000001f, 0 },

	{ X86_FEATURE_SMBA,			CPUID_EBX,  2, 0x80000020, 0 },

	{ X86_FEATURE_BMEC,			CPUID_EBX,  3, 0x80000020, 0 },