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Message-Id: <20220223052223.1202152-6-junaids@google.com> Date: Tue, 22 Feb 2022 21:21:41 -0800 From: Junaid Shahid <junaids@...gle.com> To: linux-kernel@...r.kernel.org Cc: kvm@...r.kernel.org, pbonzini@...hat.com, jmattson@...gle.com, pjt@...gle.com, oweisse@...gle.com, alexandre.chartre@...cle.com, rppt@...ux.ibm.com, dave.hansen@...ux.intel.com, peterz@...radead.org, tglx@...utronix.de, luto@...nel.org, linux-mm@...ck.org Subject: [RFC PATCH 05/47] mm: asi: Make __get_current_cr3_fast() ASI-aware When ASI is active, __get_current_cr3_fast() adjusts the returned CR3 value accordingly to reflect the actual ASI CR3. Signed-off-by: Junaid Shahid <junaids@...gle.com> --- arch/x86/include/asm/asi.h | 7 +++++++ arch/x86/mm/tlb.c | 20 ++++++++++++++++++-- 2 files changed, 25 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/asi.h b/arch/x86/include/asm/asi.h index 7702332c62e8..95557211dabd 100644 --- a/arch/x86/include/asm/asi.h +++ b/arch/x86/include/asm/asi.h @@ -112,6 +112,11 @@ static inline void asi_intr_exit(void) } } +static inline pgd_t *asi_pgd(struct asi *asi) +{ + return asi->pgd; +} + #else /* CONFIG_ADDRESS_SPACE_ISOLATION */ static inline void asi_intr_enter(void) { } @@ -120,6 +125,8 @@ static inline void asi_intr_exit(void) { } static inline void asi_init_thread_state(struct thread_struct *thread) { } +static inline pgd_t *asi_pgd(struct asi *asi) { return NULL; } + #endif /* CONFIG_ADDRESS_SPACE_ISOLATION */ #endif diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index 88d9298720dc..25bee959d1d3 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -17,6 +17,7 @@ #include <asm/cacheflush.h> #include <asm/apic.h> #include <asm/perf_event.h> +#include <asm/asi.h> #include "mm_internal.h" @@ -1073,12 +1074,27 @@ void flush_tlb_kernel_range(unsigned long start, unsigned long end) */ unsigned long __get_current_cr3_fast(void) { - unsigned long cr3 = build_cr3(this_cpu_read(cpu_tlbstate.loaded_mm)->pgd, - this_cpu_read(cpu_tlbstate.loaded_mm_asid)); + unsigned long cr3; + pgd_t *pgd; + u16 asid = this_cpu_read(cpu_tlbstate.loaded_mm_asid); + struct asi *asi = asi_get_current(); + + if (asi) + pgd = asi_pgd(asi); + else + pgd = this_cpu_read(cpu_tlbstate.loaded_mm)->pgd; + + cr3 = build_cr3(pgd, asid); /* For now, be very restrictive about when this can be called. */ VM_WARN_ON(in_nmi() || preemptible()); + /* + * CR3 is unstable if the target ASI is unrestricted + * and a restricted ASI is currently loaded. + */ + VM_WARN_ON_ONCE(asi && asi_is_target_unrestricted()); + VM_BUG_ON(cr3 != __read_cr3()); return cr3; } -- 2.35.1.473.g83b2b277ed-goog
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