ANDROID: virt: geniezone: Refactor code comments from mainline v6 accordingly

Sync changes to align with upstream-v6
[Detail]
- Response to reviewers and fix bugs accordingly

Change-Id: I4ba05da2875542f067b8b275ce68a4869dcf9ca0
Signed-off-by: Yingshiuan Pan <yingshiuan.pan@mediatek.com>
Signed-off-by: Liju-Clr Chen <liju-clr.chen@mediatek.com>
Signed-off-by: Yi-De Wu <yi-de.wu@mediatek.com>
Bug: 301179926
Link: https://lore.kernel.org/all/20230919111210.19615-1-yi-de.wu@mediatek.com/

arch/arm64/geniezone/vm.c

@@ -3,7 +3,6 @@
  * Copyright (c) 2023 MediaTek Inc.
  */
 
-#include <asm/sysreg.h>
 #include <linux/arm-smccc.h>
 #include <linux/err.h>
 #include <linux/uaccess.h>
@@ -30,10 +29,10 @@ int gzvm_arch_probe(void)
 	struct arm_smccc_res res;
 
 	arm_smccc_hvc(MT_HVC_GZVM_PROBE, 0, 0, 0, 0, 0, 0, 0, &res);
-	if (res.a0 == 0)
-		return 0;
+	if (res.a0)
+		return -ENXIO;
 
-	return -ENXIO;
+	return 0;
 }
 
 int gzvm_arch_set_memregion(u16 vm_id, size_t buf_size,
@@ -94,11 +93,7 @@ int gzvm_arch_create_vm(unsigned long vm_type)
 
 	ret = gzvm_hypcall_wrapper(MT_HVC_GZVM_CREATE_VM, vm_type, 0, 0, 0, 0,
 				   0, 0, &res);
-
-	if (ret == 0)
-		return res.a1;
-	else
-		return ret;
+	return ret ? ret : res.a1;
 }
 
 int gzvm_arch_destroy_vm(u16 vm_id)
@@ -221,12 +216,12 @@ int gzvm_vm_ioctl_arch_enable_cap(struct gzvm *gzvm,
  * gzvm_hva_to_pa_arch() - converts hva to pa with arch-specific way
  * @hva: Host virtual address.
  *
- * Return: 0 if translation error
+ * Return: GZVM_PA_ERR_BAD for translation error
  */
 u64 gzvm_hva_to_pa_arch(u64 hva)
 {
-	u64 par;
 	unsigned long flags;
+	u64 par;
 
 	local_irq_save(flags);
 	asm volatile("at s1e1r, %0" :: "r" (hva));
@@ -235,7 +230,9 @@ u64 gzvm_hva_to_pa_arch(u64 hva)
 	local_irq_restore(flags);
 
 	if (par & SYS_PAR_EL1_F)
-		return 0;
-
-	return par & PAR_PA47_MASK;
+		return GZVM_PA_ERR_BAD;
+	par = par & PAR_PA47_MASK;
+	if (!par)
+		return GZVM_PA_ERR_BAD;
+	return par;
 }

drivers/virt/geniezone/gzvm_ioeventfd.c

@@ -35,13 +35,16 @@ static bool ioeventfd_check_collision(struct gzvm *gzvm, struct gzvm_ioevent *p)
 {
 	struct gzvm_ioevent *_p;
 
-	list_for_each_entry(_p, &gzvm->ioevents, list)
+	list_for_each_entry(_p, &gzvm->ioevents, list) {
 		if (_p->addr == p->addr &&
 		    (!_p->len || !p->len ||
 		     (_p->len == p->len &&
 		      (_p->wildcard || p->wildcard ||
 		       _p->datamatch == p->datamatch))))
 			return true;
+		if (p->addr >= _p->addr && p->addr < _p->addr + _p->len)
+			return true;
+	}
 
 	return false;
 }

drivers/virt/geniezone/gzvm_main.c

@@ -3,14 +3,13 @@
  * Copyright (c) 2023 MediaTek Inc.
  */
 
-#include <linux/anon_inodes.h>
 #include <linux/device.h>
 #include <linux/file.h>
 #include <linux/kdev_t.h>
+#include <linux/miscdevice.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
-#include <linux/slab.h>
 #include <linux/gzvm_drv.h>
 
 /**
@@ -121,7 +120,7 @@ static int gzvm_drv_remove(struct platform_device *pdev)
 }
 
 static const struct of_device_id gzvm_of_match[] = {
-	{ .compatible = "mediatek,geniezone-hyp", },
+	{ .compatible = "mediatek,geniezone-hyp" },
 	{/* sentinel */},
 };
 

drivers/virt/geniezone/gzvm_vm.c

@@ -171,16 +171,21 @@ static int fill_constituents(struct mem_region_addr_range *consti,
 	return nr_pages;
 }
 
-/* register_memslot_addr_range() - Register memory region to GZ */
+/**
+ * register_memslot_addr_range() - Register memory region to GenieZone
+ * @gzvm: Pointer to struct gzvm
+ * @memslot: Pointer to struct gzvm_memslot
+ *
+ * Return: 0 for success, negative number for error
+ */
 static int
 register_memslot_addr_range(struct gzvm *gzvm, struct gzvm_memslot *memslot)
 {
 	struct gzvm_memory_region_ranges *region;
-	u32 buf_size;
+	u32 buf_size = PAGE_SIZE * 2;
 	int max_nr_consti, remain_pages;
 	u64 gfn, gfn_end;
 
-	buf_size = PAGE_SIZE * 2;
 	region = alloc_pages_exact(buf_size, GFP_KERNEL);
 	if (!region)
 		return -ENOMEM;
@@ -225,10 +230,11 @@ register_memslot_addr_range(struct gzvm *gzvm, struct gzvm_memslot *memslot)
  * @gzvm: Pointer to struct gzvm.
  * @mem: Input memory region from user.
  *
- * Return:
- * * -EXIO		- memslot is out-of-range
- * * -EFAULT		- Cannot find corresponding vma
- * * -EINVAL		- region size and vma size does not match
+ * Return: 0 for success, negative number for error
+ *
+ * -EXIO		- The memslot is out-of-range
+ * -EFAULT		- Cannot find corresponding vma
+ * -EINVAL		- Region size and VMA size mismatch
  */
 static int
 gzvm_vm_ioctl_set_memory_region(struct gzvm *gzvm,
@@ -345,7 +351,7 @@ static int gzvm_vm_ioctl_enable_cap(struct gzvm *gzvm,
 static long gzvm_vm_ioctl(struct file *filp, unsigned int ioctl,
 			  unsigned long arg)
 {
-	long ret = -ENOTTY;
+	long ret;
 	void __user *argp = (void __user *)arg;
 	struct gzvm *gzvm = filp->private_data;
 

include/linux/gzvm_drv.h

@@ -8,17 +8,23 @@
 
 #include <linux/eventfd.h>
 #include <linux/list.h>
+#include <linux/mm.h>
 #include <linux/mutex.h>
-#include <linux/miscdevice.h>
 #include <linux/gzvm.h>
 #include <linux/srcu.h>
 
+/*
+ * For the normal physical address, the highest 12 bits should be zero, so we
+ * can mask bit 62 ~ bit 52 to indicate the error physical address
+ */
+#define GZVM_PA_ERR_BAD (0x7ffULL << 52)
+
 #define GZVM_VCPU_MMAP_SIZE  PAGE_SIZE
 #define INVALID_VM_ID   0xffff
 
 /*
- * These are the efinitions of APIs between GenieZone hypervisor and driver,
- * there's no need to be visible to uapi. Furthermore, We need GenieZone
+ * These are the definitions of APIs between GenieZone hypervisor and driver,
+ * there's no need to be visible to uapi. Furthermore, we need GenieZone
  * specific error code in order to map to Linux errno
  */
 #define NO_ERROR                (0)