Re: [RFC PATCH v4 04/28] x86: Handle reduction in physical address size with SME
From: Borislav Petkov <bp@alien8.de>
Date: 2017-02-17 11:04:58
Also in:
kvm, linux-arch, linux-iommu, linux-mm, lkml
On Thu, Feb 16, 2017 at 09:42:54AM -0600, Tom Lendacky wrote:
quoted hunk ↗ jump to hunk
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> --- arch/x86/kernel/cpu/common.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index b33bc06..358208d7 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c@@ -771,11 +771,15 @@ void get_cpu_cap(struct cpuinfo_x86 *c) u64 msr; /* - * For SME, BIOS support is required. If BIOS has not - * enabled SME don't advertise the feature. + * For SME, BIOS support is required. If BIOS has + * enabled SME adjust x86_phys_bits by the SME + * physical address space reduction value. If BIOS + * has not enabled SME don't advertise the feature. */ rdmsrl(MSR_K8_SYSCFG, msr); - if (!(msr & MSR_K8_SYSCFG_MEM_ENCRYPT)) + if (msr & MSR_K8_SYSCFG_MEM_ENCRYPT) + c->x86_phys_bits -= (ebx >> 6) & 0x3f; + else eax &= ~0x01;
Right, as I mentioned yesterday, this should go to arch/x86/kernel/cpu/amd.c
--
Regards/Gruss,
Boris.
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