| Message ID | 1692309711-5573-3-git-send-email-nunodasneves@linux.microsoft.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Introduce /dev/mshv drivers | expand |
On 8/17/23 15:01, Nuno Das Neves wrote: > +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; > +} ... > +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; > + } > + > + info->eax = cpuid_eax(HYPERV_CPUID_VERSION); > + info->ebx = cpuid_ebx(HYPERV_CPUID_VERSION); > + info->ecx = cpuid_ecx(HYPERV_CPUID_VERSION); > + info->edx = cpuid_edx(HYPERV_CPUID_VERSION); > + > + return 0; > +} I can't help but notice that the ARM version does *one* call to the hardware while the x86 version does CPUID four different times, once to get *EACH* register and throwing away the other three registers each time. Also recall that CPUID is a big, fat architecturally serializing instruction. This isn't a fast path, but CPUID is about as slow as you get. Is there any reason you can't just have an x86 version of hv_get_vpreg_128() that gets the 128 bits bytes of data that comes back in the 4 CPUID registers? That might even let you share some more code.
On 8/17/2023 4:14 PM, Dave Hansen wrote: > On 8/17/23 15:01, Nuno Das Neves wrote: >> +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; >> +} > ... >> +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; >> + } >> + >> + info->eax = cpuid_eax(HYPERV_CPUID_VERSION); >> + info->ebx = cpuid_ebx(HYPERV_CPUID_VERSION); >> + info->ecx = cpuid_ecx(HYPERV_CPUID_VERSION); >> + info->edx = cpuid_edx(HYPERV_CPUID_VERSION); >> + >> + return 0; >> +} > > I can't help but notice that the ARM version does *one* call to the > hardware while the x86 version does CPUID four different times, once to > get *EACH* register and throwing away the other three registers each > time. Also recall that CPUID is a big, fat architecturally serializing > instruction. This isn't a fast path, but CPUID is about as slow as you get. > Good point, it is quite wasteful. I just went and checked cpuid.h, and of course there is a generic cpuid() function that can get all 4 at once. I will update it to use this in the next version. Thanks! > Is there any reason you can't just have an x86 version of > hv_get_vpreg_128() that gets the 128 bits bytes of data that comes back > in the 4 CPUID registers? > > That might even let you share some more code. Unfortunately, for some reason the hypervisor only lets you get this data via CPUID on x86_64, and via hypercall - i.e. hv_get_vpreg_128() - on ARM64.
diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c index f1b8a04ee9f2..53bdd3bc81ac 100644 --- a/arch/arm64/hyperv/mshyperv.c +++ b/arch/arm64/hyperv/mshyperv.c @@ -19,10 +19,19 @@ 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); + static int __init hyperv_init(void) { - struct hv_get_vp_registers_output result; - u32 a, b, c, d; + struct hv_get_vp_registers_output result; + union hv_hypervisor_version_info version; u64 guest_id; int ret; @@ -55,13 +64,11 @@ static int __init hyperv_init(void) 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; + hv_get_hypervisor_version(&version); pr_info("Hyper-V: Host Build %d.%d.%d.%d-%d-%d\n", - b >> 16, b & 0xFFFF, a, d & 0xFFFFFF, c, d >> 24); + version.major_version, version.minor_version, + version.build_number, version.service_number, + version.service_pack, version.service_branch); ret = hv_common_init(); if (ret) diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 4d38cafe6f2c..e80e503c8cf5 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -313,13 +313,30 @@ static void __init hv_smp_prepare_cpus(unsigned int max_cpus) } #endif +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; + } + + info->eax = cpuid_eax(HYPERV_CPUID_VERSION); + info->ebx = cpuid_ebx(HYPERV_CPUID_VERSION); + info->ecx = cpuid_ecx(HYPERV_CPUID_VERSION); + info->edx = cpuid_edx(HYPERV_CPUID_VERSION); + + return 0; +} +EXPORT_SYMBOL_GPL(hv_get_hypervisor_version); + 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; + union hv_hypervisor_version_info version; #ifdef CONFIG_PARAVIRT pv_info.name = "Hyper-V"; @@ -373,16 +390,11 @@ static void __init ms_hyperv_init_platform(void) /* * 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 (hv_get_hypervisor_version(&version) == 0) { + pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d\n", + version.build_number, version.major_version, + version.minor_version, version.service_pack, + version.service_branch, version.service_number); } if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS && diff --git a/include/asm-generic/hyperv-tlfs.h b/include/asm-generic/hyperv-tlfs.h index f4e4cc4f965f..373f26efa18a 100644 --- a/include/asm-generic/hyperv-tlfs.h +++ b/include/asm-generic/hyperv-tlfs.h @@ -786,6 +786,29 @@ 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; + }; +}; + /* * 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 094c57320ed1..233c976344e5 100644 --- a/include/asm-generic/mshyperv.h +++ b/include/asm-generic/mshyperv.h @@ -153,6 +153,8 @@ 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));
x86_64 and arm64 implementations to get the hypervisor version information. Store these in hv_hypervisor_version_info structure to simplify parsing the fields. Replace the existing parsing when printing the version numbers at boot. Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com> --- arch/arm64/hyperv/mshyperv.c | 23 +++++++++++------- arch/x86/kernel/cpu/mshyperv.c | 40 ++++++++++++++++++++----------- include/asm-generic/hyperv-tlfs.h | 23 ++++++++++++++++++ include/asm-generic/mshyperv.h | 2 ++ 4 files changed, 66 insertions(+), 22 deletions(-)