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| author | Andy Lutomirski <luto@kernel.org> | 2017-06-29 08:53:21 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-07-05 10:52:58 +0200 |
| commit | 660da7c9228f685b2ebe664f9fd69aaddcc420b5 (patch) | |
| tree | 363dd4d5cc99b8d78cf66d8f6c3973a1d852dcb5 /arch | |
| parent | 0790c9aad84901ca1bdc14746175549c8b5da215 (diff) | |
| download | linux-660da7c9228f685b2ebe664f9fd69aaddcc420b5.tar.bz2 | |
x86/mm: Enable CR4.PCIDE on supported systems
We can use PCID if the CPU has PCID and PGE and we're not on Xen.
By itself, this has no effect. A followup patch will start using PCID.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Nadav Amit <nadav.amit@gmail.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/6327ecd907b32f79d5aa0d466f04503bbec5df88.1498751203.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/include/asm/tlbflush.h | 8 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 22 | ||||
| -rw-r--r-- | arch/x86/xen/enlighten_pv.c | 6 |
3 files changed, 36 insertions, 0 deletions
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h index 06e997a36d49..6397275008db 100644 --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -243,6 +243,14 @@ static inline void __flush_tlb_all(void) __flush_tlb_global(); else __flush_tlb(); + + /* + * Note: if we somehow had PCID but not PGE, then this wouldn't work -- + * we'd end up flushing kernel translations for the current ASID but + * we might fail to flush kernel translations for other cached ASIDs. + * + * To avoid this issue, we force PCID off if PGE is off. + */ } static inline void __flush_tlb_one(unsigned long addr) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 904485e7b230..b95cd94ca97b 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -329,6 +329,25 @@ static __always_inline void setup_smap(struct cpuinfo_x86 *c) } } +static void setup_pcid(struct cpuinfo_x86 *c) +{ + if (cpu_has(c, X86_FEATURE_PCID)) { + if (cpu_has(c, X86_FEATURE_PGE)) { + cr4_set_bits(X86_CR4_PCIDE); + } else { + /* + * flush_tlb_all(), as currently implemented, won't + * work if PCID is on but PGE is not. Since that + * combination doesn't exist on real hardware, there's + * no reason to try to fully support it, but it's + * polite to avoid corrupting data if we're on + * an improperly configured VM. + */ + clear_cpu_cap(c, X86_FEATURE_PCID); + } + } +} + /* * Protection Keys are not available in 32-bit mode. */ @@ -1143,6 +1162,9 @@ static void identify_cpu(struct cpuinfo_x86 *c) setup_smep(c); setup_smap(c); + /* Set up PCID */ + setup_pcid(c); + /* * The vendor-specific functions might have changed features. * Now we do "generic changes." diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c index f33eef4ebd12..a136aac543c3 100644 --- a/arch/x86/xen/enlighten_pv.c +++ b/arch/x86/xen/enlighten_pv.c @@ -295,6 +295,12 @@ static void __init xen_init_capabilities(void) setup_clear_cpu_cap(X86_FEATURE_ACC); setup_clear_cpu_cap(X86_FEATURE_X2APIC); + /* + * Xen PV would need some work to support PCID: CR3 handling as well + * as xen_flush_tlb_others() would need updating. + */ + setup_clear_cpu_cap(X86_FEATURE_PCID); + if (!xen_initial_domain()) setup_clear_cpu_cap(X86_FEATURE_ACPI); |