From f0aa9058a57a4f6f03d8e08865241e141891a39a Mon Sep 17 00:00:00 2001
From: Will Deacon <willdeacon@google.com>
Date: Thu, 7 Jul 2022 15:51:27 +0100
Subject: [PATCH] Revert "ANDROID: KVM: arm64: Add __pkvm_guest_unshare_host()"

This reverts commit f3468eac6f5af403a52ece6a612117464d9b3fae.

Bug: 233587962
Signed-off-by: Will Deacon <willdeacon@google.com>
Change-Id: Ie7b3c5c296c8c3a76fb91e1db0d9ee8f8830241f
---
 arch/arm64/kvm/hyp/include/nvhe/mem_protect.h |  1 -
 arch/arm64/kvm/hyp/nvhe/mem_protect.c         | 70 -------------------
 2 files changed, 71 deletions(-)

diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
index 80878b78be2a..dc599f8380c8 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
@@ -64,7 +64,6 @@ int __pkvm_host_donate_hyp(u64 pfn, u64 nr_pages);
 int __pkvm_hyp_donate_host(u64 pfn, u64 nr_pages);
 int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct kvm_vcpu *vcpu);
 int __pkvm_guest_share_host(struct kvm_vcpu *vcpu, u64 ipa);
-int __pkvm_guest_unshare_host(struct kvm_vcpu *vcpu, u64 ipa);
 
 bool addr_is_memory(phys_addr_t phys);
 int host_stage2_idmap_locked(phys_addr_t addr, u64 size, enum kvm_pgtable_prot prot);
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index 16dcc748deb9..64e23ba18206 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -860,11 +860,6 @@ static int host_ack_donation(u64 addr, const struct pkvm_mem_transition *tx)
 	return __host_ack_transition(addr, tx, PKVM_NOPAGE);
 }
 
-static int host_ack_unshare(u64 addr, const struct pkvm_mem_transition *tx)
-{
-	return __host_ack_transition(addr, tx, PKVM_PAGE_SHARED_BORROWED);
-}
-
 static int host_complete_share(u64 addr, const struct pkvm_mem_transition *tx,
 			       enum kvm_pgtable_prot perms)
 {
@@ -873,14 +868,6 @@ static int host_complete_share(u64 addr, const struct pkvm_mem_transition *tx,
 	return __host_set_page_state_range(addr, size, PKVM_PAGE_SHARED_BORROWED);
 }
 
-static int host_complete_unshare(u64 addr, const struct pkvm_mem_transition *tx)
-{
-	u64 size = tx->nr_pages * PAGE_SIZE;
-	pkvm_id owner_id = initiator_owner_id(tx);
-
-	return host_stage2_set_owner_locked(addr, size, owner_id);
-}
-
 static int host_complete_donation(u64 addr, const struct pkvm_mem_transition *tx)
 {
 	u64 size = tx->nr_pages * PAGE_SIZE;
@@ -1114,13 +1101,6 @@ static int guest_request_share(u64 *completer_addr,
 					       PKVM_PAGE_OWNED);
 }
 
-static int guest_request_unshare(u64 *completer_addr,
-				 const struct pkvm_mem_transition *tx)
-{
-	return __guest_request_page_transition(completer_addr, tx,
-					       PKVM_PAGE_SHARED_OWNED);
-}
-
 static int __guest_initiate_page_transition(u64 *completer_addr,
 					    const struct pkvm_mem_transition *tx,
 					    enum pkvm_page_state state)
@@ -1156,13 +1136,6 @@ static int guest_initiate_share(u64 *completer_addr,
 						PKVM_PAGE_SHARED_OWNED);
 }
 
-static int guest_initiate_unshare(u64 *completer_addr,
-				  const struct pkvm_mem_transition *tx)
-{
-	return __guest_initiate_page_transition(completer_addr, tx,
-						PKVM_PAGE_OWNED);
-}
-
 static int check_share(struct pkvm_mem_share *share)
 {
 	const struct pkvm_mem_transition *tx = &share->tx;
@@ -1267,9 +1240,6 @@ static int check_unshare(struct pkvm_mem_share *share)
 	case PKVM_ID_HOST:
 		ret = host_request_unshare(&completer_addr, tx);
 		break;
-	case PKVM_ID_GUEST:
-		ret = guest_request_unshare(&completer_addr, tx);
-		break;
 	default:
 		ret = -EINVAL;
 	}
@@ -1278,9 +1248,6 @@ static int check_unshare(struct pkvm_mem_share *share)
 		return ret;
 
 	switch (tx->completer.id) {
-	case PKVM_ID_HOST:
-		ret = host_ack_unshare(completer_addr, tx);
-		break;
 	case PKVM_ID_HYP:
 		ret = hyp_ack_unshare(completer_addr, tx);
 		break;
@@ -1301,9 +1268,6 @@ static int __do_unshare(struct pkvm_mem_share *share)
 	case PKVM_ID_HOST:
 		ret = host_initiate_unshare(&completer_addr, tx);
 		break;
-	case PKVM_ID_GUEST:
-		ret = guest_initiate_unshare(&completer_addr, tx);
-		break;
 	default:
 		ret = -EINVAL;
 	}
@@ -1312,9 +1276,6 @@ static int __do_unshare(struct pkvm_mem_share *share)
 		return ret;
 
 	switch (tx->completer.id) {
-	case PKVM_ID_HOST:
-		ret = host_complete_unshare(completer_addr, tx);
-		break;
 	case PKVM_ID_HYP:
 		ret = hyp_complete_unshare(completer_addr, tx);
 		break;
@@ -1497,37 +1458,6 @@ int __pkvm_guest_share_host(struct kvm_vcpu *vcpu, u64 ipa)
 	return ret;
 }
 
-int __pkvm_guest_unshare_host(struct kvm_vcpu *vcpu, u64 ipa)
-{
-	int ret;
-	struct pkvm_mem_share share = {
-		.tx	= {
-			.nr_pages	= 1,
-			.initiator	= {
-				.id	= PKVM_ID_GUEST,
-				.addr	= ipa,
-				.guest	= {
-					.vcpu = vcpu,
-				},
-			},
-			.completer	= {
-				.id	= PKVM_ID_HOST,
-			},
-		},
-		.completer_prot	= PKVM_HOST_MEM_PROT,
-	};
-
-	host_lock_component();
-	guest_lock_component(vcpu);
-
-	ret = do_unshare(&share);
-
-	guest_unlock_component(vcpu);
-	host_unlock_component();
-
-	return ret;
-}
-
 int __pkvm_host_unshare_hyp(u64 pfn)
 {
 	int ret;