From 28b561ad9d03617418aed33b9b8c1311e940f0c8 Mon Sep 17 00:00:00 2001
From: John Baldwin <jhb@FreeBSD.org>
Date: Fri, 18 Nov 2022 10:01:57 -0800
Subject: [PATCH] vmm: Add vm_gpa_hold_global wrapper function.

This handles the case that guest pages are being held not on behalf of
a virtual CPU but globally.  Previously this was handled by passing a
vcpuid of -1 to vm_gpa_hold, but that will not work in the future when
vm_gpa_hold is changed to accept a struct vcpu pointer.

Reviewed by:	corvink, markj
Differential Revision:	https://reviews.freebsd.org/D37160
---
 sys/amd64/include/vmm.h |  2 ++
 sys/amd64/vmm/vmm.c     | 64 +++++++++++++++++++++++++++--------------
 2 files changed, 44 insertions(+), 22 deletions(-)

diff --git a/sys/amd64/include/vmm.h b/sys/amd64/include/vmm.h
index a223eb17afe..3e7dbf59fc0 100644
--- a/sys/amd64/include/vmm.h
+++ b/sys/amd64/include/vmm.h
@@ -253,6 +253,8 @@ int vm_get_memseg(struct vm *vm, int ident, size_t *len, bool *sysmem,
 vm_paddr_t vmm_sysmem_maxaddr(struct vm *vm);
 void *vm_gpa_hold(struct vm *, int vcpuid, vm_paddr_t gpa, size_t len,
     int prot, void **cookie);
+void *vm_gpa_hold_global(struct vm *vm, vm_paddr_t gpa, size_t len,
+    int prot, void **cookie);
 void vm_gpa_release(void *cookie);
 bool vm_mem_allocated(struct vm *vm, int vcpuid, vm_paddr_t gpa);
 
diff --git a/sys/amd64/vmm/vmm.c b/sys/amd64/vmm/vmm.c
index bffba382b66..a428534b873 100644
--- a/sys/amd64/vmm/vmm.c
+++ b/sys/amd64/vmm/vmm.c
@@ -965,8 +965,8 @@ vm_iommu_modify(struct vm *vm, bool map)
 
 		gpa = mm->gpa;
 		while (gpa < mm->gpa + mm->len) {
-			vp = vm_gpa_hold(vm, -1, gpa, PAGE_SIZE, VM_PROT_WRITE,
-					 &cookie);
+			vp = vm_gpa_hold_global(vm, gpa, PAGE_SIZE,
+			    VM_PROT_WRITE, &cookie);
 			KASSERT(vp != NULL, ("vm(%s) could not map gpa %#lx",
 			    vm_name(vm), gpa));
 
@@ -1032,30 +1032,14 @@ vm_assign_pptdev(struct vm *vm, int bus, int slot, int func)
 	return (error);
 }
 
-void *
-vm_gpa_hold(struct vm *vm, int vcpuid, vm_paddr_t gpa, size_t len, int reqprot,
-	    void **cookie)
+static void *
+_vm_gpa_hold(struct vm *vm, vm_paddr_t gpa, size_t len, int reqprot,
+    void **cookie)
 {
 	int i, count, pageoff;
 	struct mem_map *mm;
 	vm_page_t m;
-#ifdef INVARIANTS
-	/*
-	 * All vcpus are frozen by ioctls that modify the memory map
-	 * (e.g. VM_MMAP_MEMSEG). Therefore 'vm->memmap[]' stability is
-	 * guaranteed if at least one vcpu is in the VCPU_FROZEN state.
-	 */
-	int state;
-	KASSERT(vcpuid >= -1 && vcpuid < vm->maxcpus, ("%s: invalid vcpuid %d",
-	    __func__, vcpuid));
-	for (i = 0; i < vm->maxcpus; i++) {
-		if (vcpuid != -1 && vcpuid != i)
-			continue;
-		state = vcpu_get_state(vm, i, NULL);
-		KASSERT(state == VCPU_FROZEN, ("%s: invalid vcpu state %d",
-		    __func__, state));
-	}
-#endif
+
 	pageoff = gpa & PAGE_MASK;
 	if (len > PAGE_SIZE - pageoff)
 		panic("vm_gpa_hold: invalid gpa/len: 0x%016lx/%lu", gpa, len);
@@ -1079,6 +1063,42 @@ vm_gpa_hold(struct vm *vm, int vcpuid, vm_paddr_t gpa, size_t len, int reqprot,
 	}
 }
 
+void *
+vm_gpa_hold(struct vm *vm, int vcpuid, vm_paddr_t gpa, size_t len, int reqprot,
+    void **cookie)
+{
+#ifdef INVARIANTS
+	/*
+	 * The current vcpu should be frozen to ensure 'vm_memmap[]'
+	 * stability.
+	 */
+	int state = vcpu_get_state(vm, vcpuid, NULL);
+	KASSERT(state == VCPU_FROZEN, ("%s: invalid vcpu state %d",
+	    __func__, state));
+#endif
+	return (_vm_gpa_hold(vm, gpa, len, reqprot, cookie));
+}
+
+void *
+vm_gpa_hold_global(struct vm *vm, vm_paddr_t gpa, size_t len, int reqprot,
+    void **cookie)
+{
+#ifdef INVARIANTS
+	/*
+	 * All vcpus are frozen by ioctls that modify the memory map
+	 * (e.g. VM_MMAP_MEMSEG). Therefore 'vm->memmap[]' stability is
+	 * guaranteed if at least one vcpu is in the VCPU_FROZEN state.
+	 */
+	int state;
+	for (int i = 0; i < vm->maxcpus; i++) {
+		state = vcpu_get_state(vm, i, NULL);
+		KASSERT(state == VCPU_FROZEN, ("%s: invalid vcpu state %d",
+		    __func__, state));
+	}
+#endif
+	return (_vm_gpa_hold(vm, gpa, len, reqprot, cookie));
+}
+
 void
 vm_gpa_release(void *cookie)
 {
-- 
2.45.0