From 493cc07385cf1c6678a6159d410854b8e99aa945 Mon Sep 17 00:00:00 2001 From: Michael Kelley Date: Mon, 27 Mar 2023 06:16:07 -0700 Subject: x86/hyperv: Exclude lazy TLB mode CPUs from enlightened TLB flushes In the case where page tables are not freed, native_flush_tlb_multi() does not do a remote TLB flush on CPUs in lazy TLB mode because the CPU will flush itself at the next context switch. By comparison, the Hyper-V enlightened TLB flush does not exclude CPUs in lazy TLB mode and so performs unnecessary flushes. If we're not freeing page tables, add logic to test for lazy TLB mode when adding CPUs to the input argument to the Hyper-V TLB flush hypercall. Exclude lazy TLB mode CPUs so the behavior matches native_flush_tlb_multi() and the unnecessary flushes are avoided. Handle both the <=64 vCPU case and the _ex case for >64 vCPUs. Signed-off-by: Michael Kelley Link: https://lore.kernel.org/r/1679922967-26582-3-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu --- arch/x86/hyperv/mmu.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'arch/x86/hyperv') diff --git a/arch/x86/hyperv/mmu.c b/arch/x86/hyperv/mmu.c index 0ad2378fe6ad..8460bd35e10c 100644 --- a/arch/x86/hyperv/mmu.c +++ b/arch/x86/hyperv/mmu.c @@ -52,6 +52,11 @@ static inline int fill_gva_list(u64 gva_list[], int offset, return gva_n - offset; } +static bool cpu_is_lazy(int cpu) +{ + return per_cpu(cpu_tlbstate_shared.is_lazy, cpu); +} + static void hyperv_flush_tlb_multi(const struct cpumask *cpus, const struct flush_tlb_info *info) { @@ -60,6 +65,7 @@ static void hyperv_flush_tlb_multi(const struct cpumask *cpus, struct hv_tlb_flush *flush; u64 status; unsigned long flags; + bool do_lazy = !info->freed_tables; trace_hyperv_mmu_flush_tlb_multi(cpus, info); @@ -112,6 +118,8 @@ static void hyperv_flush_tlb_multi(const struct cpumask *cpus, goto do_ex_hypercall; for_each_cpu(cpu, cpus) { + if (do_lazy && cpu_is_lazy(cpu)) + continue; vcpu = hv_cpu_number_to_vp_number(cpu); if (vcpu == VP_INVAL) { local_irq_restore(flags); @@ -198,7 +206,8 @@ static u64 hyperv_flush_tlb_others_ex(const struct cpumask *cpus, flush->hv_vp_set.valid_bank_mask = 0; flush->hv_vp_set.format = HV_GENERIC_SET_SPARSE_4K; - nr_bank = cpumask_to_vpset(&(flush->hv_vp_set), cpus); + nr_bank = cpumask_to_vpset_skip(&flush->hv_vp_set, cpus, + info->freed_tables ? NULL : cpu_is_lazy); if (nr_bank < 0) return HV_STATUS_INVALID_PARAMETER; -- cgit v1.2.3