Commit 26097086 authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by Paolo Bonzini
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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: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Message-Id: <20221101145426.251680-12-vkuznets@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 56b5354f

arch/x86/kvm/hyperv.c

+95 −16
Original line number Diff line number Diff line
@@ -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 (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;

		}



		/*

		 * 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 (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 @@ 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);