drivers/hv/mshv_root_main.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
From: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com>
Allow MSHV_ROOT_HVCALL IOCTL on the /dev/mshv fd. This IOCTL would
execute a passthrough hypercall targeting the root/parent partition
i.e. HV_PARTITION_ID_SELF.
This will be useful for the VMM to query things like supported
synthetic processor features, supported VMM capabiliites etc.
While at it, add HVCALL_GET_PARTITION_PROPERTY_EX to the allowed list of
passthrough hypercalls.
Signed-off-by: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com>
---
drivers/hv/mshv_root_main.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/hv/mshv_root_main.c b/drivers/hv/mshv_root_main.c
index 20eda00a1b5a..98f56322cd19 100644
--- a/drivers/hv/mshv_root_main.c
+++ b/drivers/hv/mshv_root_main.c
@@ -122,6 +122,7 @@ static struct miscdevice mshv_dev = {
*/
static u16 mshv_passthru_hvcalls[] = {
HVCALL_GET_PARTITION_PROPERTY,
+ HVCALL_GET_PARTITION_PROPERTY_EX,
HVCALL_SET_PARTITION_PROPERTY,
HVCALL_INSTALL_INTERCEPT,
HVCALL_GET_VP_REGISTERS,
@@ -159,6 +160,7 @@ static int mshv_ioctl_passthru_hvcall(struct mshv_partition *partition,
unsigned int pages_order;
void *input_pg = NULL;
void *output_pg = NULL;
+ u64 pt_id = partition ? partition->pt_id : HV_PARTITION_ID_SELF;
if (copy_from_user(&args, user_args, sizeof(args)))
return -EFAULT;
@@ -180,7 +182,7 @@ static int mshv_ioctl_passthru_hvcall(struct mshv_partition *partition,
is_async = mshv_hvcall_is_async(args.code);
if (is_async) {
/* async hypercalls can only be called from partition fd */
- if (!partition_locked)
+ if (!partition || !partition_locked)
return -EINVAL;
ret = mshv_init_async_handler(partition);
if (ret)
@@ -208,7 +210,7 @@ static int mshv_ioctl_passthru_hvcall(struct mshv_partition *partition,
* NOTE: This only works because all the allowed hypercalls' input
* structs begin with a u64 partition_id field.
*/
- *(u64 *)input_pg = partition->pt_id;
+ *(u64 *)input_pg = pt_id;
if (args.reps)
status = hv_do_rep_hypercall(args.code, args.reps, 0,
@@ -226,7 +228,7 @@ static int mshv_ioctl_passthru_hvcall(struct mshv_partition *partition,
}
if (hv_result(status) == HV_STATUS_INSUFFICIENT_MEMORY) {
- ret = hv_call_deposit_pages(NUMA_NO_NODE, partition->pt_id, 1);
+ ret = hv_call_deposit_pages(NUMA_NO_NODE, pt_id, 1);
if (!ret)
ret = -EAGAIN;
} else if (!hv_result_success(status)) {
@@ -2048,6 +2050,9 @@ static long mshv_dev_ioctl(struct file *filp, unsigned int ioctl,
case MSHV_CREATE_PARTITION:
return mshv_ioctl_create_partition((void __user *)arg,
misc->this_device);
+ case MSHV_ROOT_HVCALL:
+ return mshv_ioctl_passthru_hvcall(NULL, false,
+ (void __user *)arg);
}
return -ENOTTY;
--
2.34.1Hi Anirudh,
kernel test robot noticed the following build errors:
[auto build test ERROR on linus/master]
[also build test ERROR on v6.18-rc5]
[cannot apply to next-20251114]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Anirudh-Rayabharam/Drivers-hv-ioctl-for-self-targeted-passthrough-hvcalls/20251114-182039
base: linus/master
patch link: https://lore.kernel.org/r/20251114095853.3482596-1-anirudh%40anirudhrb.com
patch subject: [PATCH] Drivers: hv: ioctl for self targeted passthrough hvcalls
config: x86_64-buildonly-randconfig-005-20251116 (https://download.01.org/0day-ci/archive/20251116/202511161617.KcDzR4sA-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251116/202511161617.KcDzR4sA-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202511161617.KcDzR4sA-lkp@intel.com/
All errors (new ones prefixed by >>):
>> drivers/hv/mshv_root_main.c:125:2: error: use of undeclared identifier 'HVCALL_GET_PARTITION_PROPERTY_EX'
125 | HVCALL_GET_PARTITION_PROPERTY_EX,
| ^
>> drivers/hv/mshv_root_main.c:175:18: error: invalid application of 'sizeof' to an incomplete type 'u16[]' (aka 'unsigned short[]')
175 | for (i = 0; i < ARRAY_SIZE(mshv_passthru_hvcalls); ++i)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/array_size.h:11:32: note: expanded from macro 'ARRAY_SIZE'
11 | #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
| ^~~~~
drivers/hv/mshv_root_main.c:179:11: error: invalid application of 'sizeof' to an incomplete type 'u16[]' (aka 'unsigned short[]')
179 | if (i >= ARRAY_SIZE(mshv_passthru_hvcalls))
| ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/array_size.h:11:32: note: expanded from macro 'ARRAY_SIZE'
11 | #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
| ^
include/linux/compiler.h:55:47: note: expanded from macro 'if'
55 | #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
| ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:57:52: note: expanded from macro '__trace_if_var'
57 | #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
| ^~~~
drivers/hv/mshv_root_main.c:179:11: error: invalid application of 'sizeof' to an incomplete type 'u16[]' (aka 'unsigned short[]')
179 | if (i >= ARRAY_SIZE(mshv_passthru_hvcalls))
| ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/array_size.h:11:32: note: expanded from macro 'ARRAY_SIZE'
11 | #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
| ^
include/linux/compiler.h:55:47: note: expanded from macro 'if'
55 | #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
| ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:57:61: note: expanded from macro '__trace_if_var'
57 | #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
| ^~~~
drivers/hv/mshv_root_main.c:179:11: error: invalid application of 'sizeof' to an incomplete type 'u16[]' (aka 'unsigned short[]')
179 | if (i >= ARRAY_SIZE(mshv_passthru_hvcalls))
| ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/array_size.h:11:32: note: expanded from macro 'ARRAY_SIZE'
11 | #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
| ^
include/linux/compiler.h:55:47: note: expanded from macro 'if'
55 | #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
| ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:57:86: note: expanded from macro '__trace_if_var'
57 | #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
| ~~~~~~~~~~~~~~~~~^~~~~
include/linux/compiler.h:68:3: note: expanded from macro '__trace_if_value'
68 | (cond) ? \
| ^~~~
5 errors generated.
vim +/HVCALL_GET_PARTITION_PROPERTY_EX +125 drivers/hv/mshv_root_main.c
117
118 /*
119 * Only allow hypercalls that have a u64 partition id as the first member of
120 * the input structure.
121 * These are sorted by value.
122 */
123 static u16 mshv_passthru_hvcalls[] = {
124 HVCALL_GET_PARTITION_PROPERTY,
> 125 HVCALL_GET_PARTITION_PROPERTY_EX,
126 HVCALL_SET_PARTITION_PROPERTY,
127 HVCALL_INSTALL_INTERCEPT,
128 HVCALL_GET_VP_REGISTERS,
129 HVCALL_SET_VP_REGISTERS,
130 HVCALL_TRANSLATE_VIRTUAL_ADDRESS,
131 HVCALL_CLEAR_VIRTUAL_INTERRUPT,
132 HVCALL_REGISTER_INTERCEPT_RESULT,
133 HVCALL_ASSERT_VIRTUAL_INTERRUPT,
134 HVCALL_GET_GPA_PAGES_ACCESS_STATES,
135 HVCALL_SIGNAL_EVENT_DIRECT,
136 HVCALL_POST_MESSAGE_DIRECT,
137 HVCALL_GET_VP_CPUID_VALUES,
138 };
139
140 static bool mshv_hvcall_is_async(u16 code)
141 {
142 switch (code) {
143 case HVCALL_SET_PARTITION_PROPERTY:
144 return true;
145 default:
146 break;
147 }
148 return false;
149 }
150
151 static int mshv_ioctl_passthru_hvcall(struct mshv_partition *partition,
152 bool partition_locked,
153 void __user *user_args)
154 {
155 u64 status;
156 int ret = 0, i;
157 bool is_async;
158 struct mshv_root_hvcall args;
159 struct page *page;
160 unsigned int pages_order;
161 void *input_pg = NULL;
162 void *output_pg = NULL;
163 u64 pt_id = partition ? partition->pt_id : HV_PARTITION_ID_SELF;
164
165 if (copy_from_user(&args, user_args, sizeof(args)))
166 return -EFAULT;
167
168 if (args.status || !args.in_ptr || args.in_sz < sizeof(u64) ||
169 mshv_field_nonzero(args, rsvd) || args.in_sz > HV_HYP_PAGE_SIZE)
170 return -EINVAL;
171
172 if (args.out_ptr && (!args.out_sz || args.out_sz > HV_HYP_PAGE_SIZE))
173 return -EINVAL;
174
> 175 for (i = 0; i < ARRAY_SIZE(mshv_passthru_hvcalls); ++i)
176 if (args.code == mshv_passthru_hvcalls[i])
177 break;
178
179 if (i >= ARRAY_SIZE(mshv_passthru_hvcalls))
180 return -EINVAL;
181
182 is_async = mshv_hvcall_is_async(args.code);
183 if (is_async) {
184 /* async hypercalls can only be called from partition fd */
185 if (!partition || !partition_locked)
186 return -EINVAL;
187 ret = mshv_init_async_handler(partition);
188 if (ret)
189 return ret;
190 }
191
192 pages_order = args.out_ptr ? 1 : 0;
193 page = alloc_pages(GFP_KERNEL, pages_order);
194 if (!page)
195 return -ENOMEM;
196 input_pg = page_address(page);
197
198 if (args.out_ptr)
199 output_pg = (char *)input_pg + PAGE_SIZE;
200 else
201 output_pg = NULL;
202
203 if (copy_from_user(input_pg, (void __user *)args.in_ptr,
204 args.in_sz)) {
205 ret = -EFAULT;
206 goto free_pages_out;
207 }
208
209 /*
210 * NOTE: This only works because all the allowed hypercalls' input
211 * structs begin with a u64 partition_id field.
212 */
213 *(u64 *)input_pg = pt_id;
214
215 if (args.reps)
216 status = hv_do_rep_hypercall(args.code, args.reps, 0,
217 input_pg, output_pg);
218 else
219 status = hv_do_hypercall(args.code, input_pg, output_pg);
220
221 if (hv_result(status) == HV_STATUS_CALL_PENDING) {
222 if (is_async) {
223 mshv_async_hvcall_handler(partition, &status);
224 } else { /* Paranoia check. This shouldn't happen! */
225 ret = -EBADFD;
226 goto free_pages_out;
227 }
228 }
229
230 if (hv_result(status) == HV_STATUS_INSUFFICIENT_MEMORY) {
231 ret = hv_call_deposit_pages(NUMA_NO_NODE, pt_id, 1);
232 if (!ret)
233 ret = -EAGAIN;
234 } else if (!hv_result_success(status)) {
235 ret = hv_result_to_errno(status);
236 }
237
238 /*
239 * Always return the status and output data regardless of result.
240 * The VMM may need it to determine how to proceed. E.g. the status may
241 * contain the number of reps completed if a rep hypercall partially
242 * succeeded.
243 */
244 args.status = hv_result(status);
245 args.reps = args.reps ? hv_repcomp(status) : 0;
246 if (copy_to_user(user_args, &args, sizeof(args)))
247 ret = -EFAULT;
248
249 if (output_pg &&
250 copy_to_user((void __user *)args.out_ptr, output_pg, args.out_sz))
251 ret = -EFAULT;
252
253 free_pages_out:
254 free_pages((unsigned long)input_pg, pages_order);
255
256 return ret;
257 }
258
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
+Nuno On Sun, Nov 16, 2025 at 04:17:08PM +0800, kernel test robot wrote: > Hi Anirudh, > > kernel test robot noticed the following build errors: > > [auto build test ERROR on linus/master] > [also build test ERROR on v6.18-rc5] > [cannot apply to next-20251114] > [If your patch is applied to the wrong git tree, kindly drop us a note. > And when submitting patch, we suggest to use '--base' as documented in > https://git-scm.com/docs/git-format-patch#_base_tree_information] > > url: https://github.com/intel-lab-lkp/linux/commits/Anirudh-Rayabharam/Drivers-hv-ioctl-for-self-targeted-passthrough-hvcalls/20251114-182039 > base: linus/master > patch link: https://lore.kernel.org/r/20251114095853.3482596-1-anirudh%40anirudhrb.com > patch subject: [PATCH] Drivers: hv: ioctl for self targeted passthrough hvcalls > config: x86_64-buildonly-randconfig-005-20251116 (https://download.01.org/0day-ci/archive/20251116/202511161617.KcDzR4sA-lkp@intel.com/config) > compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261) > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251116/202511161617.KcDzR4sA-lkp@intel.com/reproduce) > > If you fix the issue in a separate patch/commit (i.e. not just a new version of > the same patch/commit), kindly add following tags > | Reported-by: kernel test robot <lkp@intel.com> > | Closes: https://lore.kernel.org/oe-kbuild-all/202511161617.KcDzR4sA-lkp@intel.com/ > > All errors (new ones prefixed by >>): > > >> drivers/hv/mshv_root_main.c:125:2: error: use of undeclared identifier 'HVCALL_GET_PARTITION_PROPERTY_EX' > 125 | HVCALL_GET_PARTITION_PROPERTY_EX, > | ^ Anirudh, please check this. > >> drivers/hv/mshv_root_main.c:175:18: error: invalid application of 'sizeof' to an incomplete type 'u16[]' (aka 'unsigned short[]') > 175 | for (i = 0; i < ARRAY_SIZE(mshv_passthru_hvcalls); ++i) > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This is from the original patch. Perhaps adding the explicit declaration of the array size would help. Wei
On 11/17/2025 9:34 AM, Wei Liu wrote: > +Nuno > > On Sun, Nov 16, 2025 at 04:17:08PM +0800, kernel test robot wrote: >> Hi Anirudh, >> >> kernel test robot noticed the following build errors: >> >> [auto build test ERROR on linus/master] >> [also build test ERROR on v6.18-rc5] >> [cannot apply to next-20251114] >> [If your patch is applied to the wrong git tree, kindly drop us a note. >> And when submitting patch, we suggest to use '--base' as documented in >> https://git-scm.com/docs/git-format-patch#_base_tree_information] >> >> url: https://github.com/intel-lab-lkp/linux/commits/Anirudh-Rayabharam/Drivers-hv-ioctl-for-self-targeted-passthrough-hvcalls/20251114-182039 >> base: linus/master >> patch link: https://lore.kernel.org/r/20251114095853.3482596-1-anirudh%40anirudhrb.com >> patch subject: [PATCH] Drivers: hv: ioctl for self targeted passthrough hvcalls >> config: x86_64-buildonly-randconfig-005-20251116 (https://download.01.org/0day-ci/archive/20251116/202511161617.KcDzR4sA-lkp@intel.com/config) >> compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261) >> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251116/202511161617.KcDzR4sA-lkp@intel.com/reproduce) >> >> If you fix the issue in a separate patch/commit (i.e. not just a new version of >> the same patch/commit), kindly add following tags >> | Reported-by: kernel test robot <lkp@intel.com> >> | Closes: https://lore.kernel.org/oe-kbuild-all/202511161617.KcDzR4sA-lkp@intel.com/ >> >> All errors (new ones prefixed by >>): >> >>>> drivers/hv/mshv_root_main.c:125:2: error: use of undeclared identifier 'HVCALL_GET_PARTITION_PROPERTY_EX' >> 125 | HVCALL_GET_PARTITION_PROPERTY_EX, >> | ^ > > Anirudh, please check this. > This is introduced in hyperv-next, in: 59aeea195948 mshv: Add the HVCALL_GET_PARTITION_PROPERTY_EX hypercall But the bot applies the patch to linus/master, that is probably why. >>>> drivers/hv/mshv_root_main.c:175:18: error: invalid application of 'sizeof' to an incomplete type 'u16[]' (aka 'unsigned short[]') >> 175 | for (i = 0; i < ARRAY_SIZE(mshv_passthru_hvcalls); ++i) >> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > This is from the original patch. Perhaps adding the explicit declaration > of the array size would help. > I think this is just due to the earlier error... Nuno > Wei
On Mon, Nov 17, 2025 at 09:41:19AM -0800, Nuno Das Neves wrote: > On 11/17/2025 9:34 AM, Wei Liu wrote: > > +Nuno > > > > On Sun, Nov 16, 2025 at 04:17:08PM +0800, kernel test robot wrote: > >> Hi Anirudh, > >> > >> kernel test robot noticed the following build errors: > >> > >> [auto build test ERROR on linus/master] > >> [also build test ERROR on v6.18-rc5] > >> [cannot apply to next-20251114] > >> [If your patch is applied to the wrong git tree, kindly drop us a note. > >> And when submitting patch, we suggest to use '--base' as documented in > >> https://git-scm.com/docs/git-format-patch#_base_tree_information] > >> > >> url: https://github.com/intel-lab-lkp/linux/commits/Anirudh-Rayabharam/Drivers-hv-ioctl-for-self-targeted-passthrough-hvcalls/20251114-182039 > >> base: linus/master > >> patch link: https://lore.kernel.org/r/20251114095853.3482596-1-anirudh%40anirudhrb.com > >> patch subject: [PATCH] Drivers: hv: ioctl for self targeted passthrough hvcalls > >> config: x86_64-buildonly-randconfig-005-20251116 (https://download.01.org/0day-ci/archive/20251116/202511161617.KcDzR4sA-lkp@intel.com/config) > >> compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261) > >> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251116/202511161617.KcDzR4sA-lkp@intel.com/reproduce) > >> > >> If you fix the issue in a separate patch/commit (i.e. not just a new version of > >> the same patch/commit), kindly add following tags > >> | Reported-by: kernel test robot <lkp@intel.com> > >> | Closes: https://lore.kernel.org/oe-kbuild-all/202511161617.KcDzR4sA-lkp@intel.com/ > >> > >> All errors (new ones prefixed by >>): > >> > >>>> drivers/hv/mshv_root_main.c:125:2: error: use of undeclared identifier 'HVCALL_GET_PARTITION_PROPERTY_EX' > >> 125 | HVCALL_GET_PARTITION_PROPERTY_EX, > >> | ^ > > > > Anirudh, please check this. > > > This is introduced in hyperv-next, in: > 59aeea195948 mshv: Add the HVCALL_GET_PARTITION_PROPERTY_EX hypercall > > But the bot applies the patch to linus/master, that is probably why. Right. In the v2 of this patch, I used the --base argument to git format-patch as suggested by the tool above. That should help it apply the patch in the right tree. Let's see if it still complains. Anirudh > > >>>> drivers/hv/mshv_root_main.c:175:18: error: invalid application of 'sizeof' to an incomplete type 'u16[]' (aka 'unsigned short[]') > >> 175 | for (i = 0; i < ARRAY_SIZE(mshv_passthru_hvcalls); ++i) > >> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > > This is from the original patch. Perhaps adding the explicit declaration > > of the array size would help. > > > > I think this is just due to the earlier error... > > Nuno > > > Wei >
On Fri, Nov 14, 2025 at 09:58:52AM +0000, Anirudh Rayabharam wrote:
> From: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com>
>
> Allow MSHV_ROOT_HVCALL IOCTL on the /dev/mshv fd. This IOCTL would
> execute a passthrough hypercall targeting the root/parent partition
> i.e. HV_PARTITION_ID_SELF.
>
> This will be useful for the VMM to query things like supported
> synthetic processor features, supported VMM capabiliites etc.
>
> While at it, add HVCALL_GET_PARTITION_PROPERTY_EX to the allowed list of
> passthrough hypercalls.
>
> Signed-off-by: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com>
This doesn't apply to hyperv-next. What's its base?
Wei
> ---
> drivers/hv/mshv_root_main.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/hv/mshv_root_main.c b/drivers/hv/mshv_root_main.c
> index 20eda00a1b5a..98f56322cd19 100644
> --- a/drivers/hv/mshv_root_main.c
> +++ b/drivers/hv/mshv_root_main.c
> @@ -122,6 +122,7 @@ static struct miscdevice mshv_dev = {
> */
> static u16 mshv_passthru_hvcalls[] = {
> HVCALL_GET_PARTITION_PROPERTY,
> + HVCALL_GET_PARTITION_PROPERTY_EX,
> HVCALL_SET_PARTITION_PROPERTY,
> HVCALL_INSTALL_INTERCEPT,
> HVCALL_GET_VP_REGISTERS,
> @@ -159,6 +160,7 @@ static int mshv_ioctl_passthru_hvcall(struct mshv_partition *partition,
> unsigned int pages_order;
> void *input_pg = NULL;
> void *output_pg = NULL;
> + u64 pt_id = partition ? partition->pt_id : HV_PARTITION_ID_SELF;
>
> if (copy_from_user(&args, user_args, sizeof(args)))
> return -EFAULT;
> @@ -180,7 +182,7 @@ static int mshv_ioctl_passthru_hvcall(struct mshv_partition *partition,
> is_async = mshv_hvcall_is_async(args.code);
> if (is_async) {
> /* async hypercalls can only be called from partition fd */
> - if (!partition_locked)
> + if (!partition || !partition_locked)
> return -EINVAL;
> ret = mshv_init_async_handler(partition);
> if (ret)
> @@ -208,7 +210,7 @@ static int mshv_ioctl_passthru_hvcall(struct mshv_partition *partition,
> * NOTE: This only works because all the allowed hypercalls' input
> * structs begin with a u64 partition_id field.
> */
> - *(u64 *)input_pg = partition->pt_id;
> + *(u64 *)input_pg = pt_id;
>
> if (args.reps)
> status = hv_do_rep_hypercall(args.code, args.reps, 0,
> @@ -226,7 +228,7 @@ static int mshv_ioctl_passthru_hvcall(struct mshv_partition *partition,
> }
>
> if (hv_result(status) == HV_STATUS_INSUFFICIENT_MEMORY) {
> - ret = hv_call_deposit_pages(NUMA_NO_NODE, partition->pt_id, 1);
> + ret = hv_call_deposit_pages(NUMA_NO_NODE, pt_id, 1);
> if (!ret)
> ret = -EAGAIN;
> } else if (!hv_result_success(status)) {
> @@ -2048,6 +2050,9 @@ static long mshv_dev_ioctl(struct file *filp, unsigned int ioctl,
> case MSHV_CREATE_PARTITION:
> return mshv_ioctl_create_partition((void __user *)arg,
> misc->this_device);
> + case MSHV_ROOT_HVCALL:
> + return mshv_ioctl_passthru_hvcall(NULL, false,
> + (void __user *)arg);
> }
>
> return -ENOTTY;
> --
> 2.34.1
>
On Sat, Nov 15, 2025 at 06:22:40AM +0000, Wei Liu wrote:
> On Fri, Nov 14, 2025 at 09:58:52AM +0000, Anirudh Rayabharam wrote:
> > From: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com>
> >
> > Allow MSHV_ROOT_HVCALL IOCTL on the /dev/mshv fd. This IOCTL would
> > execute a passthrough hypercall targeting the root/parent partition
> > i.e. HV_PARTITION_ID_SELF.
> >
> > This will be useful for the VMM to query things like supported
> > synthetic processor features, supported VMM capabiliites etc.
> >
> > While at it, add HVCALL_GET_PARTITION_PROPERTY_EX to the allowed list of
> > passthrough hypercalls.
> >
> > Signed-off-by: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com>
>
> This doesn't apply to hyperv-next. What's its base?
Hmmm... I remember doing this on hyperv-next. This the parent I see:
commit f2329fd987a0da4759c307c46fd27c4d05bb7433
Author: Naman Jain <namjain@linux.microsoft.com>
Date: Thu Nov 13 04:41:49 2025 +0000
Drivers: hv: Introduce mshv_vtl driver
No worries, I can rebase it on hyperv-next and send it again.
Thanks,
Anirudh.
>
> Wei
>
> > ---
> > drivers/hv/mshv_root_main.c | 11 ++++++++---
> > 1 file changed, 8 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/hv/mshv_root_main.c b/drivers/hv/mshv_root_main.c
> > index 20eda00a1b5a..98f56322cd19 100644
> > --- a/drivers/hv/mshv_root_main.c
> > +++ b/drivers/hv/mshv_root_main.c
> > @@ -122,6 +122,7 @@ static struct miscdevice mshv_dev = {
> > */
> > static u16 mshv_passthru_hvcalls[] = {
> > HVCALL_GET_PARTITION_PROPERTY,
> > + HVCALL_GET_PARTITION_PROPERTY_EX,
> > HVCALL_SET_PARTITION_PROPERTY,
> > HVCALL_INSTALL_INTERCEPT,
> > HVCALL_GET_VP_REGISTERS,
> > @@ -159,6 +160,7 @@ static int mshv_ioctl_passthru_hvcall(struct mshv_partition *partition,
> > unsigned int pages_order;
> > void *input_pg = NULL;
> > void *output_pg = NULL;
> > + u64 pt_id = partition ? partition->pt_id : HV_PARTITION_ID_SELF;
> >
> > if (copy_from_user(&args, user_args, sizeof(args)))
> > return -EFAULT;
> > @@ -180,7 +182,7 @@ static int mshv_ioctl_passthru_hvcall(struct mshv_partition *partition,
> > is_async = mshv_hvcall_is_async(args.code);
> > if (is_async) {
> > /* async hypercalls can only be called from partition fd */
> > - if (!partition_locked)
> > + if (!partition || !partition_locked)
> > return -EINVAL;
> > ret = mshv_init_async_handler(partition);
> > if (ret)
> > @@ -208,7 +210,7 @@ static int mshv_ioctl_passthru_hvcall(struct mshv_partition *partition,
> > * NOTE: This only works because all the allowed hypercalls' input
> > * structs begin with a u64 partition_id field.
> > */
> > - *(u64 *)input_pg = partition->pt_id;
> > + *(u64 *)input_pg = pt_id;
> >
> > if (args.reps)
> > status = hv_do_rep_hypercall(args.code, args.reps, 0,
> > @@ -226,7 +228,7 @@ static int mshv_ioctl_passthru_hvcall(struct mshv_partition *partition,
> > }
> >
> > if (hv_result(status) == HV_STATUS_INSUFFICIENT_MEMORY) {
> > - ret = hv_call_deposit_pages(NUMA_NO_NODE, partition->pt_id, 1);
> > + ret = hv_call_deposit_pages(NUMA_NO_NODE, pt_id, 1);
> > if (!ret)
> > ret = -EAGAIN;
> > } else if (!hv_result_success(status)) {
> > @@ -2048,6 +2050,9 @@ static long mshv_dev_ioctl(struct file *filp, unsigned int ioctl,
> > case MSHV_CREATE_PARTITION:
> > return mshv_ioctl_create_partition((void __user *)arg,
> > misc->this_device);
> > + case MSHV_ROOT_HVCALL:
> > + return mshv_ioctl_passthru_hvcall(NULL, false,
> > + (void __user *)arg);
> > }
> >
> > return -ENOTTY;
> > --
> > 2.34.1
> >
On Sat, Nov 15, 2025 at 01:09:12PM +0530, Anirudh Rayabharam wrote: > On Sat, Nov 15, 2025 at 06:22:40AM +0000, Wei Liu wrote: > > On Fri, Nov 14, 2025 at 09:58:52AM +0000, Anirudh Rayabharam wrote: > > > From: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com> > > > > > > Allow MSHV_ROOT_HVCALL IOCTL on the /dev/mshv fd. This IOCTL would > > > execute a passthrough hypercall targeting the root/parent partition > > > i.e. HV_PARTITION_ID_SELF. > > > > > > This will be useful for the VMM to query things like supported > > > synthetic processor features, supported VMM capabiliites etc. > > > > > > While at it, add HVCALL_GET_PARTITION_PROPERTY_EX to the allowed list of > > > passthrough hypercalls. > > > > > > Signed-off-by: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com> > > > > This doesn't apply to hyperv-next. What's its base? > > Hmmm... I remember doing this on hyperv-next. This the parent I see: > > commit f2329fd987a0da4759c307c46fd27c4d05bb7433 > Author: Naman Jain <namjain@linux.microsoft.com> > Date: Thu Nov 13 04:41:49 2025 +0000 > > Drivers: hv: Introduce mshv_vtl driver > > No worries, I can rebase it on hyperv-next and send it again. I pulled in some patches from hyperv-fixes to hyperv-next. That's probably why. But you will see that eventually during a merge later anyway, so it is good to just rebase and resend. Wei > > Thanks, > Anirudh. >
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