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Message-ID: <97a69db6-4321-2d22-07f6-ba4b9400c688@redhat.com>
Date: Sat, 6 May 2017 11:04:41 +0200
From: Paolo Bonzini <pbonzini@...hat.com>
To: Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>,
Ingo Molnar <mingo@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
"H. Peter Anvin" <hpa@...or.com>,
Andy Lutomirski <luto@...nel.org>, Borislav Petkov <bp@...e.de>
Cc: Peter Zijlstra <peterz@...radead.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Brian Gerst <brgerst@...il.com>,
Chris Metcalf <cmetcalf@...lanox.com>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Liang Z Li <liang.z.li@...el.com>,
Masami Hiramatsu <mhiramat@...nel.org>,
Huang Rui <ray.huang@....com>, Jiri Slaby <jslaby@...e.cz>,
Jonathan Corbet <corbet@....net>,
"Michael S. Tsirkin" <mst@...hat.com>,
Paul Gortmaker <paul.gortmaker@...driver.com>,
Vlastimil Babka <vbabka@...e.cz>,
Chen Yucong <slaoub@...il.com>,
Alexandre Julliard <julliard@...ehq.org>,
Stas Sergeev <stsp@...t.ru>, Fenghua Yu <fenghua.yu@...el.com>,
"Ravi V. Shankar" <ravi.v.shankar@...el.com>,
Shuah Khan <shuah@...nel.org>, linux-kernel@...r.kernel.org,
x86@...nel.org, linux-msdos@...r.kernel.org, wine-devel@...ehq.org,
Tony Luck <tony.luck@...el.com>
Subject: Re: [PATCH v7 20/26] x86/cpufeature: Add User-Mode Instruction
Prevention definitions
On 05/05/2017 20:17, Ricardo Neri wrote:
> User-Mode Instruction Prevention is a security feature present in new
> Intel processors that, when set, prevents the execution of a subset of
> instructions if such instructions are executed in user mode (CPL > 0).
> Attempting to execute such instructions causes a general protection
> exception.
>
> The subset of instructions comprises:
>
> * SGDT - Store Global Descriptor Table
> * SIDT - Store Interrupt Descriptor Table
> * SLDT - Store Local Descriptor Table
> * SMSW - Store Machine Status Word
> * STR - Store Task Register
>
> This feature is also added to the list of disabled-features to allow
> a cleaner handling of build-time configuration.
>
> Cc: Andy Lutomirski <luto@...nel.org>
> Cc: Andrew Morton <akpm@...ux-foundation.org>
> Cc: H. Peter Anvin <hpa@...or.com>
> Cc: Borislav Petkov <bp@...e.de>
> Cc: Brian Gerst <brgerst@...il.com>
> Cc: Chen Yucong <slaoub@...il.com>
> Cc: Chris Metcalf <cmetcalf@...lanox.com>
> Cc: Dave Hansen <dave.hansen@...ux.intel.com>
> Cc: Fenghua Yu <fenghua.yu@...el.com>
> Cc: Huang Rui <ray.huang@....com>
> Cc: Jiri Slaby <jslaby@...e.cz>
> Cc: Jonathan Corbet <corbet@....net>
> Cc: Michael S. Tsirkin <mst@...hat.com>
> Cc: Paul Gortmaker <paul.gortmaker@...driver.com>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Cc: Ravi V. Shankar <ravi.v.shankar@...el.com>
> Cc: Shuah Khan <shuah@...nel.org>
> Cc: Vlastimil Babka <vbabka@...e.cz>
> Cc: Tony Luck <tony.luck@...el.com>
> Cc: Paolo Bonzini <pbonzini@...hat.com>
> Cc: Liang Z. Li <liang.z.li@...el.com>
> Cc: Alexandre Julliard <julliard@...ehq.org>
> Cc: Stas Sergeev <stsp@...t.ru>
> Cc: x86@...nel.org
> Cc: linux-msdos@...r.kernel.org
>
> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
Would it be possible to have this patch in a topic branch for KVM's
consumption?
Thanks,
Paolo
> ---
> arch/x86/include/asm/cpufeatures.h | 1 +
> arch/x86/include/asm/disabled-features.h | 8 +++++++-
> arch/x86/include/uapi/asm/processor-flags.h | 2 ++
> 3 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
> index 2701e5f..f1d61d2 100644
> --- a/arch/x86/include/asm/cpufeatures.h
> +++ b/arch/x86/include/asm/cpufeatures.h
> @@ -289,6 +289,7 @@
>
> /* Intel-defined CPU features, CPUID level 0x00000007:0 (ecx), word 16 */
> #define X86_FEATURE_AVX512VBMI (16*32+ 1) /* AVX512 Vector Bit Manipulation instructions*/
> +#define X86_FEATURE_UMIP (16*32+ 2) /* User Mode Instruction Protection */
> #define X86_FEATURE_PKU (16*32+ 3) /* Protection Keys for Userspace */
> #define X86_FEATURE_OSPKE (16*32+ 4) /* OS Protection Keys Enable */
> #define X86_FEATURE_AVX512_VPOPCNTDQ (16*32+14) /* POPCNT for vectors of DW/QW */
> diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
> index 5dff775..7adaef7 100644
> --- a/arch/x86/include/asm/disabled-features.h
> +++ b/arch/x86/include/asm/disabled-features.h
> @@ -16,6 +16,12 @@
> # define DISABLE_MPX (1<<(X86_FEATURE_MPX & 31))
> #endif
>
> +#ifdef CONFIG_X86_INTEL_UMIP
> +# define DISABLE_UMIP 0
> +#else
> +# define DISABLE_UMIP (1<<(X86_FEATURE_UMIP & 31))
> +#endif
> +
> #ifdef CONFIG_X86_64
> # define DISABLE_VME (1<<(X86_FEATURE_VME & 31))
> # define DISABLE_K6_MTRR (1<<(X86_FEATURE_K6_MTRR & 31))
> @@ -61,7 +67,7 @@
> #define DISABLED_MASK13 0
> #define DISABLED_MASK14 0
> #define DISABLED_MASK15 0
> -#define DISABLED_MASK16 (DISABLE_PKU|DISABLE_OSPKE|DISABLE_LA57)
> +#define DISABLED_MASK16 (DISABLE_PKU|DISABLE_OSPKE|DISABLE_LA57|DISABLE_UMIP)
> #define DISABLED_MASK17 0
> #define DISABLED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 18)
>
> diff --git a/arch/x86/include/uapi/asm/processor-flags.h b/arch/x86/include/uapi/asm/processor-flags.h
> index 567de50..d2c2af8 100644
> --- a/arch/x86/include/uapi/asm/processor-flags.h
> +++ b/arch/x86/include/uapi/asm/processor-flags.h
> @@ -104,6 +104,8 @@
> #define X86_CR4_OSFXSR _BITUL(X86_CR4_OSFXSR_BIT)
> #define X86_CR4_OSXMMEXCPT_BIT 10 /* enable unmasked SSE exceptions */
> #define X86_CR4_OSXMMEXCPT _BITUL(X86_CR4_OSXMMEXCPT_BIT)
> +#define X86_CR4_UMIP_BIT 11 /* enable UMIP support */
> +#define X86_CR4_UMIP _BITUL(X86_CR4_UMIP_BIT)
> #define X86_CR4_VMXE_BIT 13 /* enable VMX virtualization */
> #define X86_CR4_VMXE _BITUL(X86_CR4_VMXE_BIT)
> #define X86_CR4_SMXE_BIT 14 /* enable safer mode (TXT) */
>
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