vmm: allow vmm_getphysical to return a page held

kernel-src/arch/x86-64/syscalllog.c

@@ -200,7 +200,9 @@ static char *args[] = {
 
 #endif
 
+#ifdef SYSCALL_LOGGING
 static spinlock_t lock;
+#endif
 extern size_t freepagecount;
 __attribute__((no_caller_saved_registers)) void arch_syscall_log(int syscall, uint64_t a1, uint64_t a2, uint64_t a3, uint64_t a4, uint64_t a5, uint64_t a6) {
 #ifdef SYSCALL_LOGGING

kernel-src/include/kernel/vmm.h

@@ -101,7 +101,7 @@ void vmm_unmap(void *addr, size_t size, int flags);
 bool vmm_pagefault(void *addr, bool user, int actions);
 vmmcontext_t *vmm_newcontext();
 void vmm_switchcontext(vmmcontext_t *ctx);
-void *vmm_getphysical(void *addr);
+void *vmm_getphysical(void *addr, bool hold);
 void vmm_apinit();
 void vmm_init();
 

kernel-src/io/block/nvme.c

@@ -517,11 +517,13 @@ static int rwblocks(nvmenamespace_t *namespace, void *buffer, uintmax_t lba, siz
 		size_t docount = (done == 0) ? (PAGE_SIZE - pageoffset) / namespace->blocksize : PAGE_SIZE / namespace->blocksize;
 		docount = min(docount, count - done);
 
-		prp[0] = (uint64_t)vmm_getphysical((void *)((uintptr_t)buffer + done * namespace->blocksize));
+		prp[0] = (uint64_t)vmm_getphysical((void *)((uintptr_t)buffer + done * namespace->blocksize), true);
 		__assert(prp[0]);
 
 		err = write ? iowrite(namespace, prp, lba + done, docount) : ioread(namespace, prp, lba + done, docount);
 
+		pmm_release((void *)prp[0]);
+
 		if (err)
 			break;
 

kernel-src/io/block/vioblk.c

@@ -121,11 +121,13 @@ static int vioblk_rw(vioblkdev_t *blkdev, void *buffer, uintmax_t lba, size_t co
 		size_t docount = (done == 0) ? (PAGE_SIZE - pageoffset) / 512 : PAGE_SIZE / 512;
 		docount = min(docount, count - done);
 
-		void *bufferphys = vmm_getphysical((void *)((uintptr_t)buffer + done * 512));
+		void *bufferphys = vmm_getphysical((void *)((uintptr_t)buffer + done * 512), true);
 		__assert(bufferphys);
 
 		vioblk_enqueue(blkdev, header, bufferphys, docount * 512, status, write);
 
+		pmm_release(bufferphys);
+
 		if (*statushhdm) {
 			err = EIO;
 			break;

kernel-src/mm/vmm.c

@@ -655,7 +655,7 @@ bool vmm_pagefault(void *addr, bool user, int actions) {
 	return status;
 }
 
-void *vmm_getphysical(void *addr) {
+void *vmm_getphysical(void *addr, bool hold) {
 	addr = (void *)ROUND_DOWN((uintptr_t)addr, PAGE_SIZE);
 
 	vmmspace_t *space = getspace(addr);
@@ -666,6 +666,9 @@ void *vmm_getphysical(void *addr) {
 
 	void *physical = arch_mmu_getphysical(current_vmm_context()->pagetable, addr);
 
+	if (hold)
+		pmm_hold(physical);
+
 	MUTEX_RELEASE(&space->lock);
 	return physical + ((uintptr_t)addr - ROUND_DOWN((uintptr_t)addr, PAGE_SIZE));
 }

kernel-src/sys/syscalls/futex.c

@@ -80,7 +80,7 @@ syscallret_t syscall_futex(context_t *, uint32_t *futexp, int op, uint32_t value
 	if (ret.errno)
 		goto cleanup;
 
-	uint32_t *physical = vmm_getphysical(futexp);
+	uint32_t *physical = vmm_getphysical(futexp, false);
 	futex_t *futex = getfutex(physical);
 
 	switch (op) {