[PATCH v4 04/15] KVM: x86: Use generic async PF slot management

[Gavin Shan]

This uses the generic slot management mechanism for asynchronous
page fault by enabling CONFIG_KVM_ASYNC_PF_SLOT because the private
implementation is totally duplicate to the generic one.

The changes introduced by this is pretty mechanical and shouldn't
cause any logical changes.

Signed-off-by: Gavin Shan <gshan@xxxxxxxxxx>
---
 arch/x86/include/asm/kvm_host.h |  2 -
 arch/x86/kvm/Kconfig            |  1 +
 arch/x86/kvm/mmu/mmu.c          |  2 +-
 arch/x86/kvm/x86.c              | 86 +++------------------------------
 4 files changed, 8 insertions(+), 83 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 974cbfb1eefe..409c1e7137cd 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -810,7 +810,6 @@ struct kvm_vcpu_arch {
 
 	struct {
 		bool halted;
-		gfn_t gfns[ASYNC_PF_PER_VCPU];
 		struct gfn_to_hva_cache data;
 		u64 msr_en_val; /* MSR_KVM_ASYNC_PF_EN */
 		u64 msr_int_val; /* MSR_KVM_ASYNC_PF_INT */
@@ -1878,7 +1877,6 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu,
 			       struct kvm_async_pf *work);
 void kvm_arch_async_page_present_queued(struct kvm_vcpu *vcpu);
 bool kvm_arch_can_dequeue_async_page_present(struct kvm_vcpu *vcpu);
-extern bool kvm_find_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn);
 
 int kvm_skip_emulated_instruction(struct kvm_vcpu *vcpu);
 int kvm_complete_insn_gp(struct kvm_vcpu *vcpu, int err);
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index ac69894eab88..53a6ef30b6ee 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -32,6 +32,7 @@ config KVM
 	select HAVE_KVM_IRQ_ROUTING
 	select HAVE_KVM_EVENTFD
 	select KVM_ASYNC_PF
+	select KVM_ASYNC_PF_SLOT
 	select USER_RETURN_NOTIFIER
 	select KVM_MMIO
 	select SCHED_INFO
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index c4f4fa23320e..cd8aaa662ac2 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3799,7 +3799,7 @@ static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
 
 	if (!prefault && kvm_can_do_async_pf(vcpu)) {
 		trace_kvm_try_async_get_page(cr2_or_gpa, gfn);
-		if (kvm_find_async_pf_gfn(vcpu, gfn)) {
+		if (kvm_async_pf_find_slot(vcpu, gfn)) {
 			trace_kvm_async_pf_doublefault(cr2_or_gpa, gfn);
 			kvm_make_request(KVM_REQ_APF_HALT, vcpu);
 			return true;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 7f35d9324b99..a5f7d6122178 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -332,13 +332,6 @@ static struct kmem_cache *kvm_alloc_emulator_cache(void)
 
 static int emulator_fix_hypercall(struct x86_emulate_ctxt *ctxt);
 
-static inline void kvm_async_pf_hash_reset(struct kvm_vcpu *vcpu)
-{
-	int i;
-	for (i = 0; i < ASYNC_PF_PER_VCPU; i++)
-		vcpu->arch.apf.gfns[i] = ~0;
-}
-
 static void kvm_on_user_return(struct user_return_notifier *urn)
 {
 	unsigned slot;
@@ -854,7 +847,7 @@ void kvm_post_set_cr0(struct kvm_vcpu *vcpu, unsigned long old_cr0, unsigned lon
 {
 	if ((cr0 ^ old_cr0) & X86_CR0_PG) {
 		kvm_clear_async_pf_completion_queue(vcpu);
-		kvm_async_pf_hash_reset(vcpu);
+		kvm_async_pf_reset_slot(vcpu);
 	}
 
 	if ((cr0 ^ old_cr0) & KVM_MMU_CR0_ROLE_BITS)
@@ -3118,7 +3111,7 @@ static int kvm_pv_enable_async_pf(struct kvm_vcpu *vcpu, u64 data)
 
 	if (!kvm_pv_async_pf_enabled(vcpu)) {
 		kvm_clear_async_pf_completion_queue(vcpu);
-		kvm_async_pf_hash_reset(vcpu);
+		kvm_async_pf_reset_slot(vcpu);
 		return 0;
 	}
 
@@ -10704,7 +10697,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 
 	vcpu->arch.pat = MSR_IA32_CR_PAT_DEFAULT;
 
-	kvm_async_pf_hash_reset(vcpu);
+	kvm_async_pf_reset_slot(vcpu);
 	kvm_pmu_init(vcpu);
 
 	vcpu->arch.pending_external_vector = -1;
@@ -10828,7 +10821,7 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
 	kvmclock_reset(vcpu);
 
 	kvm_clear_async_pf_completion_queue(vcpu);
-	kvm_async_pf_hash_reset(vcpu);
+	kvm_async_pf_reset_slot(vcpu);
 	vcpu->arch.apf.halted = false;
 
 	if (vcpu->arch.guest_fpu && kvm_mpx_supported()) {
@@ -11737,73 +11730,6 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work)
 	kvm_mmu_do_page_fault(vcpu, work->cr2_or_gpa, 0, true);
 }
 
-static inline u32 kvm_async_pf_hash_fn(gfn_t gfn)
-{
-	BUILD_BUG_ON(!is_power_of_2(ASYNC_PF_PER_VCPU));
-
-	return hash_32(gfn & 0xffffffff, order_base_2(ASYNC_PF_PER_VCPU));
-}
-
-static inline u32 kvm_async_pf_next_probe(u32 key)
-{
-	return (key + 1) & (ASYNC_PF_PER_VCPU - 1);
-}
-
-static void kvm_add_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn)
-{
-	u32 key = kvm_async_pf_hash_fn(gfn);
-
-	while (vcpu->arch.apf.gfns[key] != ~0)
-		key = kvm_async_pf_next_probe(key);
-
-	vcpu->arch.apf.gfns[key] = gfn;
-}
-
-static u32 kvm_async_pf_gfn_slot(struct kvm_vcpu *vcpu, gfn_t gfn)
-{
-	int i;
-	u32 key = kvm_async_pf_hash_fn(gfn);
-
-	for (i = 0; i < ASYNC_PF_PER_VCPU &&
-		     (vcpu->arch.apf.gfns[key] != gfn &&
-		      vcpu->arch.apf.gfns[key] != ~0); i++)
-		key = kvm_async_pf_next_probe(key);
-
-	return key;
-}
-
-bool kvm_find_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn)
-{
-	return vcpu->arch.apf.gfns[kvm_async_pf_gfn_slot(vcpu, gfn)] == gfn;
-}
-
-static void kvm_del_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn)
-{
-	u32 i, j, k;
-
-	i = j = kvm_async_pf_gfn_slot(vcpu, gfn);
-
-	if (WARN_ON_ONCE(vcpu->arch.apf.gfns[i] != gfn))
-		return;
-
-	while (true) {
-		vcpu->arch.apf.gfns[i] = ~0;
-		do {
-			j = kvm_async_pf_next_probe(j);
-			if (vcpu->arch.apf.gfns[j] == ~0)
-				return;
-			k = kvm_async_pf_hash_fn(vcpu->arch.apf.gfns[j]);
-			/*
-			 * k lies cyclically in ]i,j]
-			 * |    i.k.j |
-			 * |....j i.k.| or  |.k..j i...|
-			 */
-		} while ((i <= j) ? (i < k && k <= j) : (i < k || k <= j));
-		vcpu->arch.apf.gfns[i] = vcpu->arch.apf.gfns[j];
-		i = j;
-	}
-}
-
 static inline int apf_put_user_notpresent(struct kvm_vcpu *vcpu)
 {
 	u32 reason = KVM_PV_REASON_PAGE_NOT_PRESENT;
@@ -11867,7 +11793,7 @@ bool kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu,
 	struct x86_exception fault;
 
 	trace_kvm_async_pf_not_present(work->arch.token, work->cr2_or_gpa);
-	kvm_add_async_pf_gfn(vcpu, work->arch.gfn);
+	kvm_async_pf_add_slot(vcpu, work->arch.gfn);
 
 	if (kvm_can_deliver_async_pf(vcpu) &&
 	    !apf_put_user_notpresent(vcpu)) {
@@ -11904,7 +11830,7 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
 	if (work->wakeup_all)
 		work->arch.token = ~0; /* broadcast wakeup */
 	else
-		kvm_del_async_pf_gfn(vcpu, work->arch.gfn);
+		kvm_async_pf_remove_slot(vcpu, work->arch.gfn);
 	trace_kvm_async_pf_ready(work->arch.token, work->cr2_or_gpa);
 
 	if ((work->wakeup_all || work->notpresent_injected) &&
-- 
2.23.0