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

From: Nuno Das Neves
Date: Thu Aug 05 2021 - 17:25:30 EST

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From: Wei Liu <wei.liu@xxxxxxxxxx>

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

Signed-off-by: Wei Liu <wei.liu@xxxxxxxxxx>
Signed-off-by: Nuno Das Neves <nunodasneves@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Anatol Belski <anbelski@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Wei Liu <wei.liu@xxxxxxxxxx>
---
drivers/hv/hv_call.c | 44 ++++++++++++++++++++++++++
drivers/hv/mshv.h | 7 ++++
drivers/hv/mshv_main.c | 34 ++++++++++++++++++++
include/asm-generic/hyperv-tlfs.h | 14 ++++++++
include/uapi/asm-generic/hyperv-tlfs.h | 43 +++++++++++++++++++++++++
include/uapi/linux/mshv.h | 8 +++++
6 files changed, 150 insertions(+)

diff --git a/drivers/hv/hv_call.c b/drivers/hv/hv_call.c
index 776095de9679..0900e7377826 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"
@@ -696,3 +697,46 @@ int hv_call_set_partition_property(

return hv_status_to_errno(status);
}
+
+int hv_call_translate_virtual_address(
+ u32 vp_index,
+ u64 partition_id,
+ u64 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..1a8c94edb9c5 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,
+ u64 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 06aef8b02e6c..08aff91cf260 100644
--- a/drivers/hv/mshv_main.c
+++ b/drivers/hv/mshv_main.c
@@ -411,6 +411,37 @@ 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)
{
@@ -436,6 +467,9 @@ 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 2c0dfd0b8763..2e520e7d765d 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 +902,17 @@ struct hv_set_partition_property {
u64 property_value;
} __packed;

+struct hv_translate_virtual_address_in {
+ u64 partition_id;
+ u32 vp_index;
+ u32 padding;
+ 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,
--
2.23.4

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