From a7ebb2e410f8be2b061557fd85241d75a1094221 Mon Sep 17 00:00:00 2001 From: James Hogan Date: Tue, 15 Nov 2016 00:06:05 +0000 Subject: KVM: MIPS/T&E: active_mm = init_mm in guest context MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Set init_mm as the active_mm and update mm_cpumask(current->mm) to reflect that it isn't active when in guest context. This prevents cache management code from attempting cache flushes on host virtual addresses while in guest context, for example due to a cache management IPIs or later when writing of dynamically translated code hits copy on write. We do this using helpers in static kernel code to avoid having to export init_mm to modules. Signed-off-by: James Hogan Cc: Paolo Bonzini Cc: "Radim Krčmář" Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org --- arch/mips/kvm/tlb.c | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) (limited to 'arch/mips/kvm/tlb.c') diff --git a/arch/mips/kvm/tlb.c b/arch/mips/kvm/tlb.c index ba490130b5e7..6c1f894b8754 100644 --- a/arch/mips/kvm/tlb.c +++ b/arch/mips/kvm/tlb.c @@ -382,3 +382,38 @@ void kvm_local_flush_tlb_all(void) local_irq_restore(flags); } EXPORT_SYMBOL_GPL(kvm_local_flush_tlb_all); + +/** + * kvm_mips_suspend_mm() - Suspend the active mm. + * @cpu The CPU we're running on. + * + * Suspend the active_mm, ready for a switch to a KVM guest virtual address + * space. This is left active for the duration of guest context, including time + * with interrupts enabled, so we need to be careful not to confuse e.g. cache + * management IPIs. + * + * kvm_mips_resume_mm() should be called before context switching to a different + * process so we don't need to worry about reference counting. + * + * This needs to be in static kernel code to avoid exporting init_mm. + */ +void kvm_mips_suspend_mm(int cpu) +{ + cpumask_clear_cpu(cpu, mm_cpumask(current->active_mm)); + current->active_mm = &init_mm; +} +EXPORT_SYMBOL_GPL(kvm_mips_suspend_mm); + +/** + * kvm_mips_resume_mm() - Resume the current process mm. + * @cpu The CPU we're running on. + * + * Resume the mm of the current process, after a switch back from a KVM guest + * virtual address space (see kvm_mips_suspend_mm()). + */ +void kvm_mips_resume_mm(int cpu) +{ + cpumask_set_cpu(cpu, mm_cpumask(current->mm)); + current->active_mm = current->mm; +} +EXPORT_SYMBOL_GPL(kvm_mips_resume_mm); -- cgit v1.2.3-58-ga151