ANDROID: arm64: virt: Invalidate tlb once the balloon before reporting/inflating

Instead of invalidating the tlb of the guest every page it relinquishes,
invalidate once before the host is informed about the free pages.

Bug: 315173520
Change-Id: I8450fd552a27dfc791efa15e884982aeedaa3234
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>

android/abi_gki_aarch64.stg

@@ -380788,6 +380788,15 @@ elf_symbol {
   type_id: 0xf68b6f5e
   full_name: "poll_state_synchronize_srcu"
 }
+elf_symbol {
+  id: 0x7bf7b7b1
+  name: "post_page_relinquish_tlb_inv"
+  is_defined: true
+  symbol_type: FUNCTION
+  crc: 0xcc8be82d
+  type_id: 0x10985193
+  full_name: "post_page_relinquish_tlb_inv"
+}
 elf_symbol {
   id: 0xd612789c
   name: "power_supply_am_i_supplied"
@@ -407019,6 +407028,7 @@ interface {
   symbol_id: 0x3020cd17
   symbol_id: 0x25c6452e
   symbol_id: 0x324d8228
+  symbol_id: 0x7bf7b7b1
   symbol_id: 0xd612789c
   symbol_id: 0x561323f1
   symbol_id: 0x50bfe1d8

android/abi_gki_aarch64_virtual_device

@@ -1143,6 +1143,7 @@
   page_relinquish
   page_reporting_register
   page_reporting_unregister
+  post_page_relinquish_tlb_inv
   register_oom_notifier
   register_shrinker
   __SetPageMovable

arch/arm64/include/asm/hypervisor.h

@@ -16,6 +16,7 @@ void kvm_init_ioremap_services(void);
 struct hypervisor_ops {
 #ifdef CONFIG_MEMORY_RELINQUISH
 	void (*page_relinquish)(struct page *page);
+	void (*post_page_relinquish_tlb_inv)(void);
 #endif
 };
 

arch/arm64/include/asm/mem_relinquish.h

@@ -11,5 +11,6 @@ struct page;
 
 bool kvm_has_memrelinquish_services(void);
 void page_relinquish(struct page *page);
+void post_page_relinquish_tlb_inv(void);
 
 #endif	/* __ASM_MEM_RELINQUISH_H */

arch/arm64/mm/mem_relinquish.c

@@ -69,3 +69,10 @@ void page_relinquish(struct page *page)
 		hyp_ops.page_relinquish(page);
 }
 EXPORT_SYMBOL_GPL(page_relinquish);
+
+void post_page_relinquish_tlb_inv(void)
+{
+	if (hyp_ops.post_page_relinquish_tlb_inv)
+		hyp_ops.post_page_relinquish_tlb_inv();
+}
+EXPORT_SYMBOL_GPL(post_page_relinquish_tlb_inv);

drivers/virtio/virtio_balloon.c

@@ -149,6 +149,8 @@ static void tell_host(struct virtio_balloon *vb, struct virtqueue *vq)
 
 	sg_init_one(&sg, vb->pfns, sizeof(vb->pfns[0]) * vb->num_pfns);
 
+	post_page_relinquish_tlb_inv();
+
 	/* We should always be able to add one buffer to an empty queue. */
 	virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL);
 	virtqueue_kick(vq);
@@ -177,6 +179,8 @@ static int virtballoon_free_page_report(struct page_reporting_dev_info *pr_dev_i
 	if (WARN_ON_ONCE(err))
 		return err;
 
+	post_page_relinquish_tlb_inv();
+
 	virtqueue_kick(vq);
 
 	/* When host has read buffer, this completes via balloon_ack */

include/linux/mem_relinquish.h

@@ -15,6 +15,7 @@
 
 static inline bool kvm_has_memrelinquish_services(void) { return false; }
 static inline void page_relinquish(struct page *page) { }
+static inline void post_page_relinquish_tlb_inv(void) { }
 
 #endif	/* CONFIG_MEMORY_RELINQUISH */