[PATCH 19/19] drivers/hv: Translate GVA to GPA

[Nuno Das Neves <nunodasneves@linux.microsoft.com>]

From: Wei Liu <wei.liu@kernel.org>

Introduce ioctl for translating Guest Virtual Address (GVA) to Guest
Physical Address (GPA)

Signed-off-by: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
---
 drivers/hv/hv_call.c                   | 44 ++++++++++++++++++++++++++
 drivers/hv/mshv.h                      |  7 ++++
 drivers/hv/mshv_main.c                 | 34 ++++++++++++++++++++
 include/asm-generic/hyperv-tlfs.h      | 13 ++++++++
 include/uapi/asm-generic/hyperv-tlfs.h | 43 +++++++++++++++++++++++++
 include/uapi/linux/mshv.h              |  8 +++++
 6 files changed, 149 insertions(+)

diff --git a/drivers/hv/hv_call.c b/drivers/hv/hv_call.c
index 67167fa93851..025d4e2b892f 100644
--- a/drivers/hv/hv_call.c
+++ b/drivers/hv/hv_call.c
@@ -10,6 +10,7 @@
 
 #include <linux/kernel.h>
 #include <linux/mm.h>
+#include <linux/hyperv.h>
 #include <asm/mshyperv.h>
 
 #include "mshv.h"
@@ -698,3 +699,46 @@ int hv_call_set_partition_property(
 
 	return hv_status_to_errno(status);
 }
+
+int hv_call_translate_virtual_address(
+		u32 vp_index,
+		u64 partition_id,
+		u32 flags,
+		u64 gva,
+		u64 *gpa,
+		union hv_translate_gva_result *result)
+{
+	u64 status;
+	unsigned long irq_flags;
+	struct hv_translate_virtual_address_in *input;
+	struct hv_translate_virtual_address_out *output;
+
+	local_irq_save(irq_flags);
+
+	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
+	output = *this_cpu_ptr(hyperv_pcpu_output_arg);
+
+	memset(input, 0, sizeof(*input));
+	memset(output, 0, sizeof(*output));
+
+	input->partition_id = partition_id;
+	input->vp_index = vp_index;
+	input->control_flags = flags;
+	input->gva_page = gva >> HV_HYP_PAGE_SHIFT;
+
+	status = hv_do_hypercall(HVCALL_TRANSLATE_VIRTUAL_ADDRESS, input, output);
+
+	if (!hv_result_success(status)) {
+		pr_err("%s: %s\n", __func__, hv_status_to_string(status));
+		goto out;
+	}
+
+	*result = output->translation_result;
+	*gpa = (output->gpa_page << HV_HYP_PAGE_SHIFT) + offset_in_hvpage(gva);
+
+out:
+	local_irq_restore(irq_flags);
+
+	return hv_status_to_errno(status);
+}
+
diff --git a/drivers/hv/mshv.h b/drivers/hv/mshv.h
index 8230368b4257..037291a0ad45 100644
--- a/drivers/hv/mshv.h
+++ b/drivers/hv/mshv.h
@@ -109,5 +109,12 @@ int hv_call_set_partition_property(
 		u64 partition_id,
 		u64 property_code,
 		u64 property_value);
+int hv_call_translate_virtual_address(
+		u32 vp_index,
+		u64 partition_id,
+		u32 flags,
+		u64 gva,
+		u64 *gpa,
+		union hv_translate_gva_result *result);
 
 #endif /* _MSHV_H */
diff --git a/drivers/hv/mshv_main.c b/drivers/hv/mshv_main.c
index 0d3ea80e11ef..fe6fb2668d36 100644
--- a/drivers/hv/mshv_main.c
+++ b/drivers/hv/mshv_main.c
@@ -401,6 +401,37 @@ mshv_vp_ioctl_get_set_state(struct mshv_vp *vp, void __user *user_args, bool is_
 	return 0;
 }
 
+static long
+mshv_vp_ioctl_translate_gva(struct mshv_vp *vp, void __user *user_args)
+{
+	long ret;
+	struct mshv_translate_gva args;
+	u64 gpa;
+	union hv_translate_gva_result result;
+
+	if (copy_from_user(&args, user_args, sizeof(args)))
+		return -EFAULT;
+
+	ret = hv_call_translate_virtual_address(
+			vp->index,
+			vp->partition->id,
+			args.flags,
+			args.gva,
+			&gpa,
+			&result);
+
+	if (ret)
+		return ret;
+
+	if (copy_to_user(args.result, &result, sizeof(*args.result)))
+		return -EFAULT;
+
+	if (copy_to_user(args.gpa, &gpa, sizeof(*args.gpa)))
+		return -EFAULT;
+
+	return 0;
+}
+
 static long
 mshv_vp_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
 {
@@ -426,6 +457,9 @@ mshv_vp_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
 	case MSHV_SET_VP_STATE:
 		r = mshv_vp_ioctl_get_set_state(vp, (void __user *)arg, true);
 		break;
+	case MSHV_TRANSLATE_GVA:
+		r = mshv_vp_ioctl_translate_gva(vp, (void __user *)arg);
+		break;
 	default:
 		r = -ENOTTY;
 		break;
diff --git a/include/asm-generic/hyperv-tlfs.h b/include/asm-generic/hyperv-tlfs.h
index 2869d0300032..b5e4a5003b63 100644
--- a/include/asm-generic/hyperv-tlfs.h
+++ b/include/asm-generic/hyperv-tlfs.h
@@ -158,6 +158,7 @@ struct ms_hyperv_tsc_page {
 #define HVCALL_CREATE_VP			0x004e
 #define HVCALL_GET_VP_REGISTERS			0x0050
 #define HVCALL_SET_VP_REGISTERS			0x0051
+#define HVCALL_TRANSLATE_VIRTUAL_ADDRESS	0x0052
 #define HVCALL_POST_MESSAGE			0x005c
 #define HVCALL_SIGNAL_EVENT			0x005d
 #define HVCALL_POST_DEBUG_DATA			0x0069
@@ -901,4 +902,16 @@ struct hv_set_partition_property {
 	u64 property_value;
 } __packed;
 
+struct hv_translate_virtual_address_in {
+	u64 partition_id;
+	u32 vp_index;
+	u64 control_flags;
+	u64 gva_page;
+} __packed;
+
+struct hv_translate_virtual_address_out {
+	union hv_translate_gva_result translation_result;
+	u64 gpa_page;
+} __packed;
+
 #endif
diff --git a/include/uapi/asm-generic/hyperv-tlfs.h b/include/uapi/asm-generic/hyperv-tlfs.h
index 5d8d5e89f432..95020e3a67ba 100644
--- a/include/uapi/asm-generic/hyperv-tlfs.h
+++ b/include/uapi/asm-generic/hyperv-tlfs.h
@@ -196,4 +196,47 @@ enum hv_partition_property_code {
 	HV_PARTITION_PROPERTY_PROCESSOR_VIRTUALIZATION_FEATURES		= 0x00080000,
 };
 
+enum hv_translate_gva_result_code {
+	HV_TRANSLATE_GVA_SUCCESS			= 0,
+
+	/* Translation failures. */
+	HV_TRANSLATE_GVA_PAGE_NOT_PRESENT		= 1,
+	HV_TRANSLATE_GVA_PRIVILEGE_VIOLATION		= 2,
+	HV_TRANSLATE_GVA_INVALIDE_PAGE_TABLE_FLAGS	= 3,
+
+	/* GPA access failures. */
+	HV_TRANSLATE_GVA_GPA_UNMAPPED			= 4,
+	HV_TRANSLATE_GVA_GPA_NO_READ_ACCESS		= 5,
+	HV_TRANSLATE_GVA_GPA_NO_WRITE_ACCESS		= 6,
+	HV_TRANSLATE_GVA_GPA_ILLEGAL_OVERLAY_ACCESS	= 7,
+
+	/*
+	 * Intercept for memory access by either
+	 *  - a higher VTL
+	 *  - a nested hypervisor (due to a violation of the nested page table)
+	 */
+	HV_TRANSLATE_GVA_INTERCEPT			= 8,
+
+	HV_TRANSLATE_GVA_GPA_UNACCEPTED			= 9,
+};
+
+union hv_translate_gva_result {
+	__u64 as_uint64;
+	struct {
+		__u32 result_code; /* enum hv_translate_hva_result_code */
+		__u32 cache_type : 8;
+		__u32 overlay_page : 1;
+		__u32 reserved : 23;
+	} __packed;
+};
+
+/* hv_translage_gva flags */
+#define HV_TRANSLATE_GVA_VALIDATE_READ		0x0001
+#define HV_TRANSLATE_GVA_VALIDATE_WRITE		0x0002
+#define HV_TRANSLATE_GVA_VALIDATE_EXECUTE	0x0004
+#define HV_TRANSLATE_GVA_PRIVILEGE_EXCEMP	0x0008
+#define HV_TRANSLATE_GVA_SET_PAGE_TABLE_BITS	0x0010
+#define HV_TRANSLATE_GVA_TLB_FLUSH_INHIBIT	0x0020
+#define HV_TRANSLATE_GVA_CONTROL_MASK		0x003f
+
 #endif
diff --git a/include/uapi/linux/mshv.h b/include/uapi/linux/mshv.h
index ec8281712430..0c46ce77cbb3 100644
--- a/include/uapi/linux/mshv.h
+++ b/include/uapi/linux/mshv.h
@@ -72,6 +72,13 @@ struct mshv_partition_property {
 	__u64 property_value;
 };
 
+struct mshv_translate_gva {
+	__u64 gva;
+	__u64 flags;
+	union hv_translate_gva_result *result;
+	__u64 *gpa;
+};
+
 #define MSHV_IOCTL 0xB8
 
 /* mshv device */
@@ -95,6 +102,7 @@ struct mshv_partition_property {
 #define MSHV_RUN_VP		_IOR(MSHV_IOCTL, 0x07, struct hv_message)
 #define MSHV_GET_VP_STATE	_IOWR(MSHV_IOCTL, 0x0A, struct mshv_vp_state)
 #define MSHV_SET_VP_STATE	_IOWR(MSHV_IOCTL, 0x0B, struct mshv_vp_state)
+#define MSHV_TRANSLATE_GVA	_IOWR(MSHV_IOCTL, 0x0E, struct mshv_translate_gva)
 
 /* register page mapping example:
  * struct hv_vp_register_page *regs = mmap(NULL,
-- 
2.25.1