> -----Original Message----- > From: Vitaly Kuznetsov [mailto:vkuznets@xxxxxxxxxx] > Sent: Friday, April 7, 2017 04:27 > To: devel@xxxxxxxxxxxxxxxxxxxxxx; x86@xxxxxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx; KY Srinivasan <kys@xxxxxxxxxxxxx>; > Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>; Stephen Hemminger > <sthemmin@xxxxxxxxxxxxx>; Thomas Gleixner <tglx@xxxxxxxxxxxxx>; Ingo > Molnar <mingo@xxxxxxxxxx>; H. Peter Anvin <hpa@xxxxxxxxx>; Steven > Rostedt <rostedt@xxxxxxxxxxx>; Jork Loeser <Jork.Loeser@xxxxxxxxxxxxx> > Subject: [PATCH 6/7] x86/hyper-v: use hypercall for remove TLB flush > diff --git a/arch/x86/hyperv/mmu.c b/arch/x86/hyperv/mmu.c new file > mode 100644 index 0000000..fb487cb > --- /dev/null > +++ b/arch/x86/hyperv/mmu.c > @@ -0,0 +1,128 @@ > +#include <linux/types.h> > +#include <linux/hyperv.h> > +#include <linux/slab.h> > +#include <asm/mshyperv.h> > +#include <asm/tlbflush.h> > +#include <asm/msr.h> > +#include <asm/fpu/api.h> > + > +/* > + * Arbitrary number; we need to pre-allocate per-cpu struct for doing > +TLB > + * flush hypercalls and we need to pick a size. '16' means we'll be > +able > + * to flush 16 * 4096 pages (256MB) with one hypercall. > + */ > +#define HV_MMU_MAX_GVAS 16 > + > +/* HvFlushVirtualAddressSpace*, HvFlushVirtualAddressList hypercalls */ > +struct hv_flush_pcpu { > + struct { > + __u64 address_space; > + __u64 flags; > + __u64 processor_mask; > + __u64 gva_list[HV_MMU_MAX_GVAS]; > + } flush; > + > + spinlock_t lock; > +}; Does this need an alignment declaration, so that the flush portion never crosses a page boundary when allocated with alloc_percpu()? > + > +static struct hv_flush_pcpu __percpu *pcpu_flush; > + > +static void hyperv_flush_tlb_others(const struct cpumask *cpus, > + struct mm_struct *mm, unsigned long > start, > + unsigned long end) > +{ > + struct hv_flush_pcpu *flush; > + unsigned long cur, flags; > + u64 status = -1ULL; > + int cpu, vcpu, gva_n; > + > + if (!pcpu_flush || !hv_hypercall_pg) > + goto do_native; > + > + if (cpumask_empty(cpus)) > + return; > + > + flush = this_cpu_ptr(pcpu_flush); > + spin_lock_irqsave(&flush->lock, flags); What purpose does the spinlock on the CPU-local struct serve? Would a local_irq_save() do? Could this be called from NMI context, such as from the debugger? Could this be a long-running loop, e.g. due to a large start/end range? If so, consider disabling interrupts only in the inner loop / flush the entire space? Regards, Jork _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
