From: Yu-cheng Yu <yu-cheng.yu@intel.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Tony Luck <tony.luck@intel.com>,
Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@alien8.de>,
Rik van Riel <riel@surriel.com>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Fenghua Yu <fenghua.yu@intel.com>,
Peter Zijlstra <peterz@infradead.org>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Subject: [PATCH v3 04/10] x86/fpu/xstate: Introduce XSAVES supervisor states
Date: Sat, 28 Mar 2020 09:43:01 -0700 [thread overview]
Message-ID: <20200328164307.17497-5-yu-cheng.yu@intel.com> (raw)
In-Reply-To: <20200328164307.17497-1-yu-cheng.yu@intel.com>
Enable XSAVES supervisor states by setting MSR_IA32_XSS bits according to
CPUID enumeration results. Also revise comments at various places.
v2:
- Remove printing of supervisor xstates from fpu__init_system_xstate().
Co-developed-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
---
arch/x86/kernel/fpu/xstate.c | 28 +++++++++++++++++++---------
1 file changed, 19 insertions(+), 9 deletions(-)
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index bb8b53223925..28e8229b23a7 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -228,13 +228,14 @@ void fpu__init_cpu_xstate(void)
* states can be set here.
*/
xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask_user());
+
+ /*
+ * MSR_IA32_XSS sets supervisor states managed by XSAVES.
+ */
+ if (boot_cpu_has(X86_FEATURE_XSAVES))
+ wrmsrl(MSR_IA32_XSS, xfeatures_mask_supervisor());
}
-/*
- * Note that in the future we will likely need a pair of
- * functions here: one for user xstates and the other for
- * system xstates. For now, they are the same.
- */
static bool xfeature_enabled(enum xfeature xfeature)
{
return xfeatures_mask_all & BIT_ULL(xfeature);
@@ -625,9 +626,6 @@ static void do_extra_xstate_size_checks(void)
* the size of the *user* states. If we use it to size a buffer
* that we use 'XSAVES' on, we could potentially overflow the
* buffer because 'XSAVES' saves system states too.
- *
- * Note that we do not currently set any bits on IA32_XSS so
- * 'XCR0 | IA32_XSS == XCR0' for now.
*/
static unsigned int __init get_xsaves_size(void)
{
@@ -750,7 +748,12 @@ void __init fpu__init_system_xstate(void)
cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
xfeatures_mask_all = eax + ((u64)edx << 32);
- /* Place supervisor features in xfeatures_mask_all here */
+ /*
+ * Find supervisor xstates supported by the processor.
+ */
+ cpuid_count(XSTATE_CPUID, 1, &eax, &ebx, &ecx, &edx);
+ xfeatures_mask_all |= ecx + ((u64)edx << 32);
+
if ((xfeatures_mask_user() & XFEATURE_MASK_FPSSE) != XFEATURE_MASK_FPSSE) {
/*
* This indicates that something really unexpected happened
@@ -810,6 +813,13 @@ void fpu__resume_cpu(void)
*/
if (boot_cpu_has(X86_FEATURE_XSAVE))
xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask_user());
+
+ /*
+ * Restore IA32_XSS. The same CPUID bit enumerates support
+ * of XSAVES and MSR_IA32_XSS.
+ */
+ if (boot_cpu_has(X86_FEATURE_XSAVES))
+ wrmsrl(MSR_IA32_XSS, xfeatures_mask_supervisor());
}
/*
--
2.21.0
next prev parent reply other threads:[~2020-03-28 16:44 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-28 16:42 [PATCH v3 00/10] Support XSAVES supervisor states Yu-cheng Yu
2020-03-28 16:42 ` [PATCH v3 01/10] x86/fpu/xstate: Rename validate_xstate_header() to validate_user_xstate_header() Yu-cheng Yu
2020-04-28 17:11 ` Borislav Petkov
2020-04-28 17:15 ` Yu-cheng Yu
2020-03-28 16:42 ` [PATCH v3 02/10] x86/fpu/xstate: Define new macros for supervisor and user xstates Yu-cheng Yu
2020-03-28 16:43 ` [PATCH v3 03/10] x86/fpu/xstate: Separate user and supervisor xfeatures mask Yu-cheng Yu
2020-03-28 16:43 ` Yu-cheng Yu [this message]
2020-03-28 16:43 ` [PATCH v3 05/10] x86/fpu/xstate: Define new functions for clearing fpregs and xstates Yu-cheng Yu
2020-04-29 9:27 ` Borislav Petkov
2020-04-29 16:09 ` Yu-cheng Yu
2020-04-29 16:06 ` Yu-cheng Yu
2020-04-29 16:39 ` Borislav Petkov
2020-04-29 17:02 ` Yu-cheng Yu
2020-04-29 17:32 ` Borislav Petkov
2020-04-29 17:42 ` Yu-cheng Yu
2020-04-29 19:10 ` Yu-cheng Yu
2020-03-28 16:43 ` [PATCH v3 06/10] x86/fpu/xstate: Update sanitize_restored_xstate() for supervisor xstates Yu-cheng Yu
2020-05-07 13:11 ` Borislav Petkov
2020-05-07 15:55 ` Yu-cheng Yu
2020-03-28 16:43 ` [PATCH v3 07/10] x86/fpu/xstate: Update copy_kernel_to_xregs_err() for XSAVES supervisor states Yu-cheng Yu
2020-05-07 13:28 ` Borislav Petkov
2020-05-07 15:58 ` Yu-cheng Yu
2020-03-28 16:43 ` [PATCH v3 08/10] x86/fpu: Introduce copy_supervisor_to_kernel() Yu-cheng Yu
2020-03-28 16:43 ` [PATCH v3 09/10] x86/fpu/xstate: Preserve supervisor states for slow path of __fpu__restore_sig() Yu-cheng Yu
2020-05-10 8:46 ` Borislav Petkov
2020-05-11 20:16 ` Yu-cheng Yu
2020-03-28 16:43 ` [PATCH v3 10/10] x86/fpu/xstate: Restore supervisor states for signal return Yu-cheng Yu
2020-05-10 8:49 ` Borislav Petkov
2020-05-11 20:20 ` Yu-cheng Yu
2020-05-11 20:27 ` [PATCH v3 00/10] Support XSAVES supervisor states Borislav Petkov
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