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.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 arch/x86/kvm/hyperv.c | 100 +++++++++++++++++++++++++++++++++++++-----
 1 file changed, 88 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 762b0b699fdf..956072592e2f 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c

@@ -1806,32 +1806,82 @@ 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);
        u64 entry = KVM_HV_TLB_FLUSHALL_ENTRY;
+       unsigned long flags;
 
        if (!hv_vcpu)
                return;
 
        tlb_flush_fifo = &hv_vcpu->tlb_flush_fifo;
 
-       kfifo_in_spinlocked(&tlb_flush_fifo->entries, &entry, 1, &tlb_flush_fifo->write_lock);
+       spin_lock_irqsave(&tlb_flush_fifo->write_lock, flags);
+
+       /*
+        * 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, &entry, 1);

+               kvm_vcpu_flush_tlb_guest(vcpu);
                return;
+       }
 
        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;
+
+out_flush_all:
+       kvm_vcpu_flush_tlb_guest(vcpu);
        kfifo_reset_out(&tlb_flush_fifo->entries);
 }
 

@@ -1841,11 +1891,21 @@ 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

@@ -1861,10 +1921,12 @@ 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,

@@ -1888,10 +1950,12 @@ 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,

@@ -1907,25 +1971,37 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc)

                        return HV_STATUS_INVALID_HYPERCALL_INPUT;
 
                if (all_cpus)
-                       goto do_flush;
+                       goto read_flush_entries;
 
                if (!hc->var_cnt)
                        goto ret_success;
 
-               if (kvm_get_sparse_vp_set(kvm, hc, sparse_banks, 2,
-                                         offsetof(struct hv_tlb_flush_ex,
-                                                  hv_vp_set.bank_contents)))
+               if (kvm_get_sparse_vp_set(kvm, hc, sparse_banks, consumed_xmm_halves,
+                                         data_offset))
+                       return HV_STATUS_INVALID_HYPERCALL_INPUT;
+               data_offset += hc->var_cnt * sizeof(sparse_banks[0]);
+               consumed_xmm_halves += hc->var_cnt;
+       }
+
+read_flush_entries:
+       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 {

@@ -1935,7 +2011,7 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc)

                        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);