From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 9F7C92749D7; Wed, 1 Oct 2025 22:32:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759357971; cv=none; b=ON8ejwAh8OYeNKfx4+mAirc7JIbbUau3somjziA2JtoNMWpPre3gszPvdJw9+1I18a+/ZQkMdUqah5FvyblFDq+5Amh4lnbhLZcZ7Gt3OKgiT3OyS4IZgkq3034XQufxIO8kBe7yjA4/yp3RRsGwCkrNgJxHRMkmzyJZrLBNggw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759357971; c=relaxed/simple; bh=WGK33wCKTm008rU5ePGwtX9RHGETzOZWgGS3aCLrp7Y=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=liY/qej9oCcBiQqM1jszW2WiaRH4TnvbkJMyvbraDZsjai06Fu2YNzGaOnP+cTBFbG8xpJLOxfz/MGW0+z99CXSPY8yZFYkPqBZisOzjDu88sjmK5UqmN9bdM2MRAOm+aq0pq9Wy4c4j0o85MruBP/VkPXcVh0veUzuYl9geAO0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=LVSvz0A7; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="LVSvz0A7" Received: from [100.65.224.47] (unknown [20.236.10.120]) by linux.microsoft.com (Postfix) with ESMTPSA id 0B225211AF3E; Wed, 1 Oct 2025 15:32:47 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 0B225211AF3E DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1759357968; bh=oUX7L8avRavk71gK1uwbRnrb9ly6HfBLRWi7RqKz3GQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=LVSvz0A7FbPunBXC5+6MIbEG2CpPcDsHW57DjYHuMJ3X+DOZtclaAxJck6kUwbg7q R8sKMGl0oOVWcmyehuLhMmTkcUqbNYffjCkQyNJfyowj33GIAUNi7U69zK0yN7AX5Y JKQiKL8YsSNncd0F5ltyU7DQgtnpjBHAnt4gEtTw= Message-ID: Date: Wed, 1 Oct 2025 15:32:46 -0700 Precedence: bulk X-Mailing-List: linux-hyperv@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 2/5] mshv: Add the HVCALL_GET_PARTITION_PROPERTY_EX hypercall To: Michael Kelley , "linux-hyperv@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "prapal@linux.microsoft.com" , "easwar.hariharan@linux.microsoft.com" , "tiala@microsoft.com" , "anirudh@anirudhrb.com" , "paekkaladevi@linux.microsoft.com" , "skinsburskii@linux.microsoft.com" Cc: "kys@microsoft.com" , "haiyangz@microsoft.com" , "wei.liu@kernel.org" , "decui@microsoft.com" References: <1758903795-18636-1-git-send-email-nunodasneves@linux.microsoft.com> <1758903795-18636-3-git-send-email-nunodasneves@linux.microsoft.com> Content-Language: en-US From: Nuno Das Neves In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/29/2025 10:55 AM, Michael Kelley wrote: > From: Nuno Das Neves Sent: Friday, September 26, 2025 9:23 AM >> >> From: Purna Pavan Chandra Aekkaladevi >> >> This hypercall can be used to fetch extended properties of a >> partition. Extended properties are properties with values larger than >> a u64. Some of these also need additional input arguments. >> >> Add helper function for using the hypercall in the mshv_root driver. >> >> Signed-off-by: Purna Pavan Chandra Aekkaladevi >> Signed-off-by: Nuno Das Neves >> Reviewed-by: Anirudh Rayabharam >> Reviewed-by: Praveen K Paladugu >> Reviewed-by: Easwar Hariharan >> --- >> drivers/hv/mshv_root.h | 2 ++ >> drivers/hv/mshv_root_hv_call.c | 31 ++++++++++++++++++++++++++ >> include/hyperv/hvgdk_mini.h | 1 + >> include/hyperv/hvhdk.h | 40 ++++++++++++++++++++++++++++++++++ >> include/hyperv/hvhdk_mini.h | 26 ++++++++++++++++++++++ >> 5 files changed, 100 insertions(+) >> >> diff --git a/drivers/hv/mshv_root.h b/drivers/hv/mshv_root.h >> index e3931b0f1269..4aeb03bea6b6 100644 >> --- a/drivers/hv/mshv_root.h >> +++ b/drivers/hv/mshv_root.h >> @@ -303,6 +303,8 @@ int hv_call_unmap_stat_page(enum hv_stats_object_type type, >> int hv_call_modify_spa_host_access(u64 partition_id, struct page **pages, >> u64 page_struct_count, u32 host_access, >> u32 flags, u8 acquire); >> +int hv_call_get_partition_property_ex(u64 partition_id, u64 property_code, u64 arg, >> + void *property_value, size_t property_value_sz); >> >> extern struct mshv_root mshv_root; >> extern enum hv_scheduler_type hv_scheduler_type; >> diff --git a/drivers/hv/mshv_root_hv_call.c b/drivers/hv/mshv_root_hv_call.c >> index c9c274f29c3c..3fd3cce23f69 100644 >> --- a/drivers/hv/mshv_root_hv_call.c >> +++ b/drivers/hv/mshv_root_hv_call.c >> @@ -590,6 +590,37 @@ int hv_call_unmap_vp_state_page(u64 partition_id, u32 vp_index, u32 type, >> return hv_result_to_errno(status); >> } >> >> +int hv_call_get_partition_property_ex(u64 partition_id, u64 property_code, >> + u64 arg, void *property_value, >> + size_t property_value_sz) >> +{ >> + u64 status; >> + unsigned long flags; >> + struct hv_input_get_partition_property_ex *input; >> + struct hv_output_get_partition_property_ex *output; >> + >> + local_irq_save(flags); >> + input = *this_cpu_ptr(hyperv_pcpu_input_arg); >> + output = *this_cpu_ptr(hyperv_pcpu_output_arg); >> + >> + memset(input, 0, sizeof(*input)); >> + input->partition_id = partition_id; >> + input->property_code = property_code; >> + input->arg = arg; >> + status = hv_do_hypercall(HVCALL_GET_PARTITION_PROPERTY_EX, input, output); >> + >> + if (!hv_result_success(status)) { >> + hv_status_debug(status, "\n"); >> + local_irq_restore(flags); > > Nit: It would be marginally better to do the local_irq_restore() first, and then > output the error message so that interrupts are not disabled any longer than > needed. > Good point >> + return hv_result_to_errno(status); >> + } >> + memcpy(property_value, &output->property_value, property_value_sz); >> + >> + local_irq_restore(flags); >> + >> + return 0; >> +} >> + >> int >> hv_call_clear_virtual_interrupt(u64 partition_id) >> { >> diff --git a/include/hyperv/hvgdk_mini.h b/include/hyperv/hvgdk_mini.h >> index 1be7f6a02304..ff4325fb623a 100644 >> --- a/include/hyperv/hvgdk_mini.h >> +++ b/include/hyperv/hvgdk_mini.h >> @@ -490,6 +490,7 @@ union hv_vp_assist_msr_contents { /* >> HV_REGISTER_VP_ASSIST_PAGE */ >> #define HVCALL_GET_VP_STATE 0x00e3 >> #define HVCALL_SET_VP_STATE 0x00e4 >> #define HVCALL_GET_VP_CPUID_VALUES 0x00f4 >> +#define HVCALL_GET_PARTITION_PROPERTY_EX 0x0101 >> #define HVCALL_MMIO_READ 0x0106 >> #define HVCALL_MMIO_WRITE 0x0107 >> >> diff --git a/include/hyperv/hvhdk.h b/include/hyperv/hvhdk.h >> index b4067ada02cf..416c0d45b793 100644 >> --- a/include/hyperv/hvhdk.h >> +++ b/include/hyperv/hvhdk.h >> @@ -376,6 +376,46 @@ struct hv_input_set_partition_property { >> u64 property_value; >> } __packed; >> >> +union hv_partition_property_arg { >> + u64 as_uint64; >> + struct { >> + union { >> + u32 arg; >> + u32 vp_index; >> + }; >> + u16 reserved0; >> + u8 reserved1; >> + u8 object_type; >> + } __packed; >> +}; >> + >> +struct hv_input_get_partition_property_ex { >> + u64 partition_id; >> + u32 property_code; /* enum hv_partition_property_code */ >> + u32 padding; >> + union { >> + union hv_partition_property_arg arg_data; >> + u64 arg; > > This union, and the "u64 arg" member, seems redundant since > union hv_partition_property_arg already has a member "as_uint64". > > Maybe this is just being copied from the Windows versions of these > structures, in which case I realize there are constraints on what you > want to change or fix, and you can ignore my comment. > Yeah, this is just due to it coming from the Windows code. I prefer to keep it as close as possible unless it is actually a bug (like missing padding which has happened a couple of times). >> + }; >> +} __packed; >> + >> +/* >> + * NOTE: Should use hv_input_set_partition_property_ex_header to compute this >> + * size, but hv_input_get_partition_property_ex is identical so it suffices >> + */ >> +#define HV_PARTITION_PROPERTY_EX_MAX_VAR_SIZE \ >> + (HV_HYP_PAGE_SIZE - sizeof(struct hv_input_get_partition_property_ex)) >> + >> +union hv_partition_property_ex { >> + u8 buffer[HV_PARTITION_PROPERTY_EX_MAX_VAR_SIZE]; > > It's unclear what this "buffer" field is trying to do, and particularly its size. > The comment above references hv_input_set_partition_property_ex_header, > which doesn't exist in the Linux code. And why is the max size of the output > buffer reduced by the size of the header of the input to "set partition property"? > Yes, hv_input_set_partition_property_ex_header doesn't exist here, it's from the Windows code (although in CAPs). It's identical to hv_input_get_partition_property_ex. I decided to just use hv_input_get_partition_property_ex instead of introducing the unused header struct, for now. I'm not certain what the buffer is used for, but I suspect it's for data that doesn't fit with the other partition property structs. Maybe some raw/unstructured data. hv_partition_property_ex has to be that size because it is also used (not yet, in linux) for setting properties, and the set hypercall has a header as mentioned above, so the entire struct mustn't exceed a page in size - i.e.: struct hv_input_set_partition_property_ex { hv_input_set_partition_property_ex_header header; hv_partition_property_ex property_value; }; But we don't need this yet. Thanks Nuno >> + struct hv_partition_property_vmm_capabilities vmm_capabilities; >> + /* More fields to be filled in when needed */ >> +}; >> + >> +struct hv_output_get_partition_property_ex { >> + union hv_partition_property_ex property_value; >> +} __packed; >> + >> enum hv_vp_state_page_type { >> HV_VP_STATE_PAGE_REGISTERS = 0, >> HV_VP_STATE_PAGE_INTERCEPT_MESSAGE = 1, >> diff --git a/include/hyperv/hvhdk_mini.h b/include/hyperv/hvhdk_mini.h >> index 858f6a3925b3..bf2ce27dfcc5 100644 >> --- a/include/hyperv/hvhdk_mini.h >> +++ b/include/hyperv/hvhdk_mini.h >> @@ -96,8 +96,34 @@ enum hv_partition_property_code { >> HV_PARTITION_PROPERTY_XSAVE_STATES = 0x00060007, >> HV_PARTITION_PROPERTY_MAX_XSAVE_DATA_SIZE = 0x00060008, >> HV_PARTITION_PROPERTY_PROCESSOR_CLOCK_FREQUENCY = 0x00060009, >> + >> + /* Extended properties with larger property values */ >> + HV_PARTITION_PROPERTY_VMM_CAPABILITIES = 0x00090007, >> }; >> >> +#define HV_PARTITION_VMM_CAPABILITIES_BANK_COUNT 1 >> +#define HV_PARTITION_VMM_CAPABILITIES_RESERVED_BITFIELD_COUNT 59 >> + >> +struct hv_partition_property_vmm_capabilities { >> + u16 bank_count; >> + u16 reserved[3]; >> + union { >> + u64 as_uint64[HV_PARTITION_VMM_CAPABILITIES_BANK_COUNT]; >> + struct { >> + u64 map_gpa_preserve_adjustable: 1; >> + u64 vmm_can_provide_overlay_gpfn: 1; >> + u64 vp_affinity_property: 1; >> +#if IS_ENABLED(CONFIG_ARM64) >> + u64 vmm_can_provide_gic_overlay_locations: 1; >> +#else >> + u64 reservedbit3: 1; >> +#endif >> + u64 assignable_synthetic_proc_features: 1; >> + u64 reserved0: HV_PARTITION_VMM_CAPABILITIES_RESERVED_BITFIELD_COUNT; >> + } __packed; >> + }; >> +} __packed; >> + >> enum hv_snp_status { >> HV_SNP_STATUS_NONE = 0, >> HV_SNP_STATUS_AVAILABLE = 1, >> -- >> 2.34.1 >>