From 260970862c88b4130e9e12be023c7e2c2d37a966 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Tue, 1 Nov 2022 15:53:49 +0100 Subject: [PATCH] KVM: x86: hyper-v: Handle HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST{,EX} calls gently Currently, HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST{,EX} calls are handled the exact same way as HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE{,EX}: by flushing the whole VPID and this is sub-optimal. Switch to handling these requests with 'flush_tlb_gva()' hooks instead. Use the newly introduced TLB flush fifo to queue the requests. Reviewed-by: Sean Christopherson Signed-off-by: Vitaly Kuznetsov Signed-off-by: Paolo Bonzini Message-Id: <20221101145426.251680-12-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/hyperv.c | 111 ++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 95 insertions(+), 16 deletions(-) diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index 3ba7e2d2fbbd..6868c478617c 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -1800,7 +1800,14 @@ static u64 kvm_get_sparse_vp_set(struct kvm *kvm, struct kvm_hv_hcall *hc, sparse_banks, consumed_xmm_halves, offset); } -static void hv_tlb_flush_enqueue(struct kvm_vcpu *vcpu) +static int kvm_hv_get_tlb_flush_entries(struct kvm *kvm, struct kvm_hv_hcall *hc, u64 entries[], + int consumed_xmm_halves, gpa_t offset) +{ + return kvm_hv_get_hc_data(kvm, hc, hc->rep_cnt, hc->rep_cnt, + entries, consumed_xmm_halves, offset); +} + +static void hv_tlb_flush_enqueue(struct kvm_vcpu *vcpu, u64 *entries, int count) { struct kvm_vcpu_hv_tlb_flush_fifo *tlb_flush_fifo; struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu); @@ -1811,24 +1818,64 @@ static void hv_tlb_flush_enqueue(struct kvm_vcpu *vcpu) tlb_flush_fifo = &hv_vcpu->tlb_flush_fifo; - kfifo_in_spinlocked_noirqsave(&tlb_flush_fifo->entries, &flush_all_entry, - 1, &tlb_flush_fifo->write_lock); + spin_lock(&tlb_flush_fifo->write_lock); + + /* + * All entries should fit on the fifo leaving one free for 'flush all' + * entry in case another request comes in. In case there's not enough + * space, just put 'flush all' entry there. + */ + if (count && entries && count < kfifo_avail(&tlb_flush_fifo->entries)) { + WARN_ON(kfifo_in(&tlb_flush_fifo->entries, entries, count) != count); + goto out_unlock; + } + + /* + * Note: full fifo always contains 'flush all' entry, no need to check the + * return value. + */ + kfifo_in(&tlb_flush_fifo->entries, &flush_all_entry, 1); + +out_unlock: + spin_unlock(&tlb_flush_fifo->write_lock); } int kvm_hv_vcpu_flush_tlb(struct kvm_vcpu *vcpu) { struct kvm_vcpu_hv_tlb_flush_fifo *tlb_flush_fifo; struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu); + u64 entries[KVM_HV_TLB_FLUSH_FIFO_SIZE]; + int i, j, count; + gva_t gva; - if (!hv_vcpu) + if (!tdp_enabled || !hv_vcpu) return -EINVAL; tlb_flush_fifo = &hv_vcpu->tlb_flush_fifo; + count = kfifo_out(&tlb_flush_fifo->entries, entries, KVM_HV_TLB_FLUSH_FIFO_SIZE); + + for (i = 0; i < count; i++) { + if (entries[i] == KVM_HV_TLB_FLUSHALL_ENTRY) + goto out_flush_all; + + /* + * Lower 12 bits of 'address' encode the number of additional + * pages to flush. + */ + gva = entries[i] & PAGE_MASK; + for (j = 0; j < (entries[i] & ~PAGE_MASK) + 1; j++) + static_call(kvm_x86_flush_tlb_gva)(vcpu, gva + j * PAGE_SIZE); + + ++vcpu->stat.tlb_flush; + } + return 0; + +out_flush_all: kfifo_reset_out(&tlb_flush_fifo->entries); - /* Precise flushing isn't implemented yet. */ - return -EOPNOTSUPP; + /* Fall back to full flush. */ + return -ENOSPC; } static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) @@ -1837,11 +1884,21 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) struct hv_tlb_flush_ex flush_ex; struct hv_tlb_flush flush; DECLARE_BITMAP(vcpu_mask, KVM_MAX_VCPUS); + /* + * Normally, there can be no more than 'KVM_HV_TLB_FLUSH_FIFO_SIZE' + * entries on the TLB flush fifo. The last entry, however, needs to be + * always left free for 'flush all' entry which gets placed when + * there is not enough space to put all the requested entries. + */ + u64 __tlb_flush_entries[KVM_HV_TLB_FLUSH_FIFO_SIZE - 1]; + u64 *tlb_flush_entries; u64 valid_bank_mask; u64 sparse_banks[KVM_HV_MAX_SPARSE_VCPU_SET_BITS]; struct kvm_vcpu *v; unsigned long i; bool all_cpus; + int consumed_xmm_halves = 0; + gpa_t data_offset; /* * The Hyper-V TLFS doesn't allow more than 64 sparse banks, e.g. the @@ -1857,10 +1914,12 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) flush.address_space = hc->ingpa; flush.flags = hc->outgpa; flush.processor_mask = sse128_lo(hc->xmm[0]); + consumed_xmm_halves = 1; } else { if (unlikely(kvm_read_guest(kvm, hc->ingpa, &flush, sizeof(flush)))) return HV_STATUS_INVALID_HYPERCALL_INPUT; + data_offset = sizeof(flush); } trace_kvm_hv_flush_tlb(flush.processor_mask, @@ -1884,10 +1943,12 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) flush_ex.flags = hc->outgpa; memcpy(&flush_ex.hv_vp_set, &hc->xmm[0], sizeof(hc->xmm[0])); + consumed_xmm_halves = 2; } else { if (unlikely(kvm_read_guest(kvm, hc->ingpa, &flush_ex, sizeof(flush_ex)))) return HV_STATUS_INVALID_HYPERCALL_INPUT; + data_offset = sizeof(flush_ex); } trace_kvm_hv_flush_tlb_ex(flush_ex.hv_vp_set.valid_bank_mask, @@ -1902,26 +1963,44 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) if (hc->var_cnt != hweight64(valid_bank_mask)) return HV_STATUS_INVALID_HYPERCALL_INPUT; - if (all_cpus) - goto do_flush; + if (!all_cpus) { + if (!hc->var_cnt) + goto ret_success; - if (!hc->var_cnt) - goto ret_success; + if (kvm_get_sparse_vp_set(kvm, hc, sparse_banks, + consumed_xmm_halves, data_offset)) + return HV_STATUS_INVALID_HYPERCALL_INPUT; + } + + /* + * Hyper-V TLFS doesn't explicitly forbid non-empty sparse vCPU + * banks (and, thus, non-zero 'var_cnt') for the 'all vCPUs' + * case (HV_GENERIC_SET_ALL). Always adjust data_offset and + * consumed_xmm_halves to make sure TLB flush entries are read + * from the correct offset. + */ + data_offset += hc->var_cnt * sizeof(sparse_banks[0]); + consumed_xmm_halves += hc->var_cnt; + } - if (kvm_get_sparse_vp_set(kvm, hc, sparse_banks, 2, - offsetof(struct hv_tlb_flush_ex, - hv_vp_set.bank_contents))) + if (hc->code == HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE || + hc->code == HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX || + hc->rep_cnt > ARRAY_SIZE(__tlb_flush_entries)) { + tlb_flush_entries = NULL; + } else { + if (kvm_hv_get_tlb_flush_entries(kvm, hc, __tlb_flush_entries, + consumed_xmm_halves, data_offset)) return HV_STATUS_INVALID_HYPERCALL_INPUT; + tlb_flush_entries = __tlb_flush_entries; } -do_flush: /* * vcpu->arch.cr3 may not be up-to-date for running vCPUs so we can't * analyze it here, flush TLB regardless of the specified address space. */ if (all_cpus) { kvm_for_each_vcpu(i, v, kvm) - hv_tlb_flush_enqueue(v); + hv_tlb_flush_enqueue(v, tlb_flush_entries, hc->rep_cnt); kvm_make_all_cpus_request(kvm, KVM_REQ_HV_TLB_FLUSH); } else { @@ -1931,7 +2010,7 @@ do_flush: v = kvm_get_vcpu(kvm, i); if (!v) continue; - hv_tlb_flush_enqueue(v); + hv_tlb_flush_enqueue(v, tlb_flush_entries, hc->rep_cnt); } kvm_make_vcpus_request_mask(kvm, KVM_REQ_HV_TLB_FLUSH, vcpu_mask); -- 2.11.0