On 3/7/2024 11:22 AM, Michael Kelley wrote:
> From: Nuno Das Neves <nunodasneves@xxxxxxxxxxxxxxxxxxx> Sent: Wednesday, March 6, 2024 4:48 PM
>>
>> Introduce x86_64 and arm64 functions for getting the hypervisor version
>> information and storing it in a structure for simpler parsing.
>>
>> Use the new function to get and parse the version at boot time. While at
>> it, print the version in the same format for each architecture, and move
>> the printing code to hv_common_init() so it is not duplicated.
>
> Isn't the format already the same for x86 and ARM64? A couple of
> years ago they didn't match. But that was fixed in commit eeda29db98f4.
>
You're correct - I will amend the commit message. Thanks!
>>
>> Signed-off-by: Nuno Das Neves <nunodasneves@xxxxxxxxxxxxxxxxxxx>
>> Acked-by: Wei Liu <wei.liu@xxxxxxxxxx>
>> ---
>> arch/arm64/hyperv/mshyperv.c | 19 ++++++++---------
>> arch/x86/kernel/cpu/mshyperv.c | 35 ++++++++++++++-----------------
>> drivers/hv/hv_common.c | 9 ++++++++
>> include/asm-generic/hyperv-tlfs.h | 23 ++++++++++++++++++++
>> include/asm-generic/mshyperv.h | 2 ++
>> 5 files changed, 59 insertions(+), 29 deletions(-)
>>
>> diff --git a/arch/arm64/hyperv/mshyperv.c
>> b/arch/arm64/hyperv/mshyperv.c
>> index f1b8a04ee9f2..55dc224d466d 100644
>> --- a/arch/arm64/hyperv/mshyperv.c
>> +++ b/arch/arm64/hyperv/mshyperv.c
>> @@ -19,10 +19,18 @@
>>
>> static bool hyperv_initialized;
>>
>> +int hv_get_hypervisor_version(union hv_hypervisor_version_info *info)
>> +{
>> + hv_get_vpreg_128(HV_REGISTER_HYPERVISOR_VERSION,
>> + (struct hv_get_vp_registers_output *)info);
>> +
>> + return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(hv_get_hypervisor_version);
>
> I don't think this need to be exported, at least not for the usage in
> this patch. The caller in hv_common.c is never part of a module -- it's
> always built-in. But maybe you are anticipating future use cases
> from a module?
>
Yes, it will be used in a module eventually. Do you think I should remove
this and the below export until they are actually needed?
>> +
>> static int __init hyperv_init(void)
>> {
>> struct hv_get_vp_registers_output result;
>> - u32 a, b, c, d;
>> u64 guest_id;
>> int ret;
>>
>> @@ -54,15 +62,6 @@ static int __init hyperv_init(void)
>> ms_hyperv.features, ms_hyperv.priv_high, ms_hyperv.hints,
>> ms_hyperv.misc_features);
>>
>> - /* Get information about the Hyper-V host version */
>> - hv_get_vpreg_128(HV_REGISTER_HYPERVISOR_VERSION, &result);
>> - a = result.as32.a;
>> - b = result.as32.b;
>> - c = result.as32.c;
>> - d = result.as32.d;
>> - pr_info("Hyper-V: Host Build %d.%d.%d.%d-%d-%d\n",
>> - b >> 16, b & 0xFFFF, a, d & 0xFFFFFF, c, d >> 24);
>> -
>> ret = hv_common_init();
>> if (ret)
>> return ret;
>> diff --git a/arch/x86/kernel/cpu/mshyperv.c
>> b/arch/x86/kernel/cpu/mshyperv.c
>> index d306f6184cee..03a3445faf7a 100644
>> --- a/arch/x86/kernel/cpu/mshyperv.c
>> +++ b/arch/x86/kernel/cpu/mshyperv.c
>> @@ -350,13 +350,25 @@ static void __init reduced_hw_init(void)
>> x86_init.irqs.pre_vector_init = x86_init_noop;
>> }
>>
>> +int hv_get_hypervisor_version(union hv_hypervisor_version_info *info)
>> +{
>> + unsigned int hv_max_functions;
>> +
>> + hv_max_functions = cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS);
>> + if (hv_max_functions < HYPERV_CPUID_VERSION) {
>> + pr_err("%s: Could not detect Hyper-V version\n", __func__);
>> + return -ENODEV;
>> + }
>> +
>> + cpuid(HYPERV_CPUID_VERSION, &info->eax, &info->ebx, &info->ecx, &info->edx);
>> +
>> + return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(hv_get_hypervisor_version);
>
> Same for this EXPORT.
>>> +
>> static void __init ms_hyperv_init_platform(void)
>> {
>> int hv_max_functions_eax;
>> - int hv_host_info_eax;
>> - int hv_host_info_ebx;
>> - int hv_host_info_ecx;
>> - int hv_host_info_edx;
>>
>> #ifdef CONFIG_PARAVIRT
>> pv_info.name = "Hyper-V";
>> @@ -407,21 +419,6 @@ static void __init ms_hyperv_init_platform(void)
>> pr_info("Hyper-V: running on a nested hypervisor\n");
>> }
>>
>> - /*
>> - * Extract host information.
>> - */
>> - if (hv_max_functions_eax >= HYPERV_CPUID_VERSION) {
>> - hv_host_info_eax = cpuid_eax(HYPERV_CPUID_VERSION);
>> - hv_host_info_ebx = cpuid_ebx(HYPERV_CPUID_VERSION);
>> - hv_host_info_ecx = cpuid_ecx(HYPERV_CPUID_VERSION);
>> - hv_host_info_edx = cpuid_edx(HYPERV_CPUID_VERSION);
>> -
>> - pr_info("Hyper-V: Host Build %d.%d.%d.%d-%d-%d\n",
>> - hv_host_info_ebx >> 16, hv_host_info_ebx & 0xFFFF,
>> - hv_host_info_eax, hv_host_info_edx & 0xFFFFFF,
>> - hv_host_info_ecx, hv_host_info_edx >> 24);
>> - }
>> -
>> if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&
>> ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
>> x86_platform.calibrate_tsc = hv_get_tsc_khz;
>> diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
>> index 2f1dd4b07f9a..4d72c528af68 100644
>> --- a/drivers/hv/hv_common.c
>> +++ b/drivers/hv/hv_common.c
>> @@ -278,6 +278,15 @@ static void hv_kmsg_dump_register(void)
>> int __init hv_common_init(void)
>> {
>> int i;
>> + union hv_hypervisor_version_info version;
>> +
>> + /* Get information about the Hyper-V host version */
>> + if (hv_get_hypervisor_version(&version) == 0) {
>
> The usual idiom would be:
>
> if (!hv_get_hypervisor_version(&version)) {
>
Thanks, I'll change it.
>> + pr_info("Hyper-V: Host Build %d.%d.%d.%d-%d-%d\n",
>> + version.major_version, version.minor_version,
>> + version.build_number, version.service_number,
>> + version.service_pack, version.service_branch);
>> + }
>>
>> if (hv_is_isolation_supported())
>> sysctl_record_panic_msg = 0;
>> diff --git a/include/asm-generic/hyperv-tlfs.h b/include/asm-generic/hyperv-tlfs.h
>> index 3d1b31f90ed6..32514a870b98 100644
>> --- a/include/asm-generic/hyperv-tlfs.h
>> +++ b/include/asm-generic/hyperv-tlfs.h
>> @@ -817,6 +817,29 @@ struct hv_input_unmap_device_interrupt {
>> #define HV_SOURCE_SHADOW_NONE 0x0
>> #define HV_SOURCE_SHADOW_BRIDGE_BUS_RANGE 0x1
>>
>> +/*
>> + * Version info reported by hypervisor
>> + */
>> +union hv_hypervisor_version_info {
>> + struct {
>> + u32 build_number;
>> +
>> + u32 minor_version : 16;
>> + u32 major_version : 16;
>> +
>> + u32 service_pack;
>> +
>> + u32 service_number : 24;
>> + u32 service_branch : 8;
>> + };
>> + struct {
>> + u32 eax;
>> + u32 ebx;
>> + u32 ecx;
>> + u32 edx;
>
> Nit: These names are x86-isms appearing in the generic portion
> of hyperv-tlfs.h. On the ARM64 side I had called the four parts
> "a", "b", "c", and "d" to be slightly more generic. But if want to
> keep the x86 register names, I won't object.
> > Michael
>
Good point. It's worth noting that these are now only used on the x86
side as arguments to cpuid(), so I might just leave them as-is.
Another option would be to add an x86-only union for this purpose:
union hv_x86_hypervisor_version_info {
struct hv_hypervisor_version_info info;
struct {
u32 eax;
u32 ebx;
u32 ecx;
u32 edx;
};
};
But that is probably overkill...
Thanks for the comments!
Nuno
>> + };
>> +};
>> +
>> /*
>> * The whole argument should fit in a page to be able to pass to the hypervisor
>> * in one hypercall.
>> diff --git a/include/asm-generic/mshyperv.h b/include/asm-
>> generic/mshyperv.h
>> index 04424a446bb7..452b7c089b71 100644
>> --- a/include/asm-generic/mshyperv.h
>> +++ b/include/asm-generic/mshyperv.h
>> @@ -161,6 +161,8 @@ static inline void vmbus_signal_eom(struct
>> hv_message *msg, u32 old_msg_type)
>> }
>> }
>>
>> +int hv_get_hypervisor_version(union hv_hypervisor_version_info *info);
>> +
>> void hv_setup_vmbus_handler(void (*handler)(void));
>> void hv_remove_vmbus_handler(void);
>> void hv_setup_stimer0_handler(void (*handler)(void));
>> --
>> 2.25.1
>>
