Commit 9af9b940 authored Jul 17, 2017 by Tom Lendacky Committed by Ingo Molnar Jul 18, 2017

x86/cpu/AMD: Handle SME reduction in physical address size



When System Memory Encryption (SME) is enabled, the physical address
space is reduced. Adjust the x86_phys_bits value to reflect this
reduction.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Toshimitsu Kani <toshi.kani@hpe.com>
Cc: kasan-dev@googlegroups.com
Cc: kvm@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-efi@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/593c037a3cad85ba92f3d061ffa7462e9ce3531d.1500319216.git.thomas.lendacky@amd.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 872cbefd

arch/x86/kernel/cpu/amd.c

+13 −11

Original line number	Original line	Diff line number	Diff line
	@@ -613,20 +613,22 @@ static void early_init_amd(struct cpuinfo_x86 *c)
	set_cpu_bug(c, X86_BUG_AMD_E400);		set_cpu_bug(c, X86_BUG_AMD_E400);

	/*		/*
	* BIOS support is required for SME. If BIOS has not enabled SME		* BIOS support is required for SME. If BIOS has enabled SME then
	* then don't advertise the feature (set in scattered.c). Also,		* adjust x86_phys_bits by the SME physical address space reduction
	* since the SME support requires long mode, don't advertise the		* value. If BIOS has not enabled SME then don't advertise the
	* feature under CONFIG_X86_32.		* feature (set in scattered.c). Also, since the SME support requires
			* long mode, don't advertise the feature under CONFIG_X86_32.
	*/		*/
	if (cpu_has(c, X86_FEATURE_SME)) {		if (cpu_has(c, X86_FEATURE_SME)) {
	if (IS_ENABLED(CONFIG_X86_32)) {
	clear_cpu_cap(c, X86_FEATURE_SME);
	} else {
	u64 msr;		u64 msr;

	/* Check if SME is enabled */		/* Check if SME is enabled */
	rdmsrl(MSR_K8_SYSCFG, msr);		rdmsrl(MSR_K8_SYSCFG, msr);
	if (!(msr & MSR_K8_SYSCFG_MEM_ENCRYPT))		if (msr & MSR_K8_SYSCFG_MEM_ENCRYPT) {
			c->x86_phys_bits -= (cpuid_ebx(0x8000001f) >> 6) & 0x3f;
			if (IS_ENABLED(CONFIG_X86_32))
			clear_cpu_cap(c, X86_FEATURE_SME);
			} else {
	clear_cpu_cap(c, X86_FEATURE_SME);		clear_cpu_cap(c, X86_FEATURE_SME);
	}		}
	}		}