[PATCH v9 18/21] virt: geniezone: Add memory relinquish support

[Yi-De Wu]

From: "Jerry Wang" <ze-yu.wang@xxxxxxxxxxxx>

Unpin the pages when VM relinquish the pages or is destroyed.

Signed-off-by: Jerry Wang <ze-yu.wang@xxxxxxxxxxxx>
Signed-off-by: Yingshiuan Pan <yingshiuan.pan@xxxxxxxxxxxx>
Signed-off-by: Liju-Clr Chen <liju-clr.chen@xxxxxxxxxxxx>
Signed-off-by: Yi-De Wu <yi-de.wu@xxxxxxxxxxxx>
---
 drivers/virt/geniezone/gzvm_exception.c | 23 ++++++++++++
 drivers/virt/geniezone/gzvm_mmu.c       | 49 +++++++++++++++++++++++++
 drivers/virt/geniezone/gzvm_vcpu.c      |  6 ++-
 include/linux/gzvm_drv.h                |  2 +
 include/uapi/linux/gzvm.h               |  5 +++
 5 files changed, 83 insertions(+), 2 deletions(-)

diff --git a/drivers/virt/geniezone/gzvm_exception.c b/drivers/virt/geniezone/gzvm_exception.c
index 31fdb4ae8db4..af26d1c82791 100644
--- a/drivers/virt/geniezone/gzvm_exception.c
+++ b/drivers/virt/geniezone/gzvm_exception.c
@@ -37,3 +37,26 @@ bool gzvm_handle_guest_exception(struct gzvm_vcpu *vcpu)
 	else
 		return false;
 }
+
+/**
+ * gzvm_handle_guest_hvc() - Handle guest hvc
+ * @vcpu: Pointer to struct gzvm_vcpu struct
+ * Return:
+ * * true - This hvc has been processed, no need to back to VMM.
+ * * false - This hvc has not been processed, require userspace.
+ */
+bool gzvm_handle_guest_hvc(struct gzvm_vcpu *vcpu)
+{
+	unsigned long ipa;
+	int ret;
+
+	switch (vcpu->run->hypercall.args[0]) {
+	case GZVM_HVC_MEM_RELINQUISH:
+		ipa = vcpu->run->hypercall.args[1];
+		ret = gzvm_handle_relinquish(vcpu, ipa);
+		return (ret == 0) ? true : false;
+	default:
+		break;
+	}
+	return false;
+}
diff --git a/drivers/virt/geniezone/gzvm_mmu.c b/drivers/virt/geniezone/gzvm_mmu.c
index cf619b3833aa..cf9484736874 100644
--- a/drivers/virt/geniezone/gzvm_mmu.c
+++ b/drivers/virt/geniezone/gzvm_mmu.c
@@ -131,6 +131,36 @@ static int gzvm_insert_ppage(struct gzvm *vm, struct gzvm_pinned_page *ppage)
 	return 0;
 }
 
+static int rb_ppage_cmp(const void *key, const struct rb_node *node)
+{
+	struct gzvm_pinned_page *p = container_of(node,
+						  struct gzvm_pinned_page,
+						  node);
+	phys_addr_t ipa = (phys_addr_t)key;
+
+	return (ipa < p->ipa) ? -1 : (ipa > p->ipa);
+}
+
+/* Invoker of this function is responsible for locking */
+static int gzvm_remove_ppage(struct gzvm *vm, phys_addr_t ipa)
+{
+	struct gzvm_pinned_page *ppage;
+	struct rb_node *node;
+
+	node = rb_find((void *)ipa, &vm->pinned_pages, rb_ppage_cmp);
+
+	if (node)
+		rb_erase(node, &vm->pinned_pages);
+	else
+		return 0;
+
+	ppage = container_of(node, struct gzvm_pinned_page, node);
+	unpin_user_pages_dirty_lock(&ppage->page, 1, true);
+	kfree(ppage);
+
+	return 0;
+}
+
 static int pin_one_page(struct gzvm *vm, unsigned long hva, u64 gpa)
 {
 	unsigned int flags = FOLL_HWPOISON | FOLL_LONGTERM | FOLL_WRITE;
@@ -167,6 +197,25 @@ static int pin_one_page(struct gzvm *vm, unsigned long hva, u64 gpa)
 	return ret;
 }
 
+/**
+ * gzvm_handle_relinquish() - Handle memory relinquish request from hypervisor
+ *
+ * @vcpu: Pointer to struct gzvm_vcpu_run in userspace
+ * @ipa: Start address(gpa) of a reclaimed page
+ *
+ * Return: Always return 0 because there are no cases of failure
+ */
+int gzvm_handle_relinquish(struct gzvm_vcpu *vcpu, phys_addr_t ipa)
+{
+	struct gzvm *vm = vcpu->gzvm;
+
+	mutex_lock(&vm->mem_lock);
+	gzvm_remove_ppage(vm, ipa);
+	mutex_unlock(&vm->mem_lock);
+
+	return 0;
+}
+
 int gzvm_vm_allocate_guest_page(struct gzvm *vm, struct gzvm_memslot *slot,
 				u64 gfn, u64 *pfn)
 {
diff --git a/drivers/virt/geniezone/gzvm_vcpu.c b/drivers/virt/geniezone/gzvm_vcpu.c
index 455ae2e4285c..86c690749277 100644
--- a/drivers/virt/geniezone/gzvm_vcpu.c
+++ b/drivers/virt/geniezone/gzvm_vcpu.c
@@ -113,12 +113,14 @@ static long gzvm_vcpu_run(struct gzvm_vcpu *vcpu, void __user *argp)
 		 * it's geniezone's responsibility to fill corresponding data
 		 * structure
 		 */
+		case GZVM_EXIT_HYPERCALL:
+			if (!gzvm_handle_guest_hvc(vcpu))
+				need_userspace = true;
+			break;
 		case GZVM_EXIT_EXCEPTION:
 			if (!gzvm_handle_guest_exception(vcpu))
 				need_userspace = true;
 			break;
-		case GZVM_EXIT_HYPERCALL:
-			fallthrough;
 		case GZVM_EXIT_DEBUG:
 			fallthrough;
 		case GZVM_EXIT_FAIL_ENTRY:
diff --git a/include/linux/gzvm_drv.h b/include/linux/gzvm_drv.h
index bb47de2cf5a2..2e50ee3011e8 100644
--- a/include/linux/gzvm_drv.h
+++ b/include/linux/gzvm_drv.h
@@ -178,6 +178,8 @@ int gzvm_arch_inform_exit(u16 vm_id);
 int gzvm_find_memslot(struct gzvm *vm, u64 gpa);
 int gzvm_handle_page_fault(struct gzvm_vcpu *vcpu);
 bool gzvm_handle_guest_exception(struct gzvm_vcpu *vcpu);
+int gzvm_handle_relinquish(struct gzvm_vcpu *vcpu, phys_addr_t ipa);
+bool gzvm_handle_guest_hvc(struct gzvm_vcpu *vcpu);
 
 int gzvm_arch_create_device(u16 vm_id, struct gzvm_create_device *gzvm_dev);
 int gzvm_arch_inject_irq(struct gzvm *gzvm, unsigned int vcpu_idx,
diff --git a/include/uapi/linux/gzvm.h b/include/uapi/linux/gzvm.h
index ce4c80bf254c..205fcf7cdfa7 100644
--- a/include/uapi/linux/gzvm.h
+++ b/include/uapi/linux/gzvm.h
@@ -189,6 +189,11 @@ enum {
 	GZVM_EXCEPTION_PAGE_FAULT = 0x1,
 };
 
+/* hypercall definitions of GZVM_EXIT_HYPERCALL */
+enum {
+	GZVM_HVC_MEM_RELINQUISH = 0xc6000009,
+};
+
 /**
  * struct gzvm_vcpu_run: Same purpose as kvm_run, this struct is
  *			 shared between userspace, kernel and
-- 
2.18.0