On 2/19/2025 6:07 PM, Michael Kelley wrote: > From: Nuno Das Neves <nunodasneves@xxxxxxxxxxxxxxxxxxx> Sent: Wednesday, February 19, 2025 3:53 PM >> >> On 2/19/2025 11:46 AM, Michael Kelley wrote: >>> From: Nuno Das Neves <nunodasneves@xxxxxxxxxxxxxxxxxxx> Sent: Tuesday, >> February 11, 2025 2:22 PM >>>> >>>> Introduce CONFIG_MSHV_ROOT as a tristate to enable root partition >>>> booting and future mshv driver functionality. >>> >>> This statement could use a bit more explanation as to "why". Something >>> like: >>> >>> Running in the root partition is a unique and specialized case that requires >>> additional code. The config option allows kernels built to run as a normal >>> Hyper-V guest to exclude this code, which is important since significant >>> additional code specific to the root partition is expected to be added over >>> time. >>> >> >> This sounds good to me >> >>> Related, what's the thinking behind making CONFIG_MSHV_ROOT be >>> tri-state? Obviously, it would allow most of the root partition code >>> to be loaded as a module instead of built-in to the kernel image, but is that >>> a useful scenario given the unique nature of running in the root partition? >>> Since the root partition environment is very specific and constrained, >>> perhaps just always building the root partition code into the kernel >>> makes sense. I'm asking purely as a question because I'm not familiar with >>> the details of how a root partition kernel is likely to be setup & run. If >>> possible, give a short explanation for the "why tri-state" question. >>> Remember, that's what commit message are for -- to answer the "why" >>> question as much as to summarize the "what" question. >>> >> >> In the past it enabled quicker development: I would iterate on the driver >> code and just rebuild and reinsert the module. I'll admit I haven't used that >> workflow in a while so I'm not sure how useful it still is. >> >> Is there a *downside* (from upstream perspective) to keeping it a tristate >> that I'm not aware of? e.g. Would it be difficult to change it to a bool in >> future if we decide we really don't need it? > > OK -- I had not thought about the development workflow, and that's valid. > There's no downside to keeping it tri-state that I'm aware of. And I think it > would be easy to change to just a Boolean in the future if tri-state > isn't really useful. It was just one of those things that surprised me > a little bit, and I was wondering "why". :-) > Ok great, I will mention it is primarily to aid development. >> >> While we're on this topic, do you know if CONFIG_HYPERV=m is ever used, and >> why? > > Yes, it is definitely used by the distro vendors. They want to have a single > product release that is useable pretty much everywhere. So they don't > want to burden the main kernel binary with Hyper-V code that > wouldn't be used on bare metal, or a KVM/QEMU VM, etc. Azure images > might be a little more specific to Hyper-V, and might have the Hyper-V > code built-in -- it depends on the distro vendor. I don't remember having > taken a census to know which approach predominates, but my guess is > "=m". > Good to know! >> >>>> >>>> Change hv_root_partition into a function which always returns false >>>> if CONFIG_MSHV_ROOT=n. >>> >>> Again, help answer the "why" question. I think the goal is related to >>> the above by allowing the compiler to optimize away any "if (root partition)" >>> code when building for a normal Hyper-V guest. >>> Forgot to respond here last email - Yep, I will explain it more clearly as you suggest. >>>> >>>> Introduce hv_current_partition_type to store the type of partition >>>> (guest, root, or other kinds in future), and hv_identify_partition_type() >>>> to it up early in Hyper-V initialization. >>>> >>>> Signed-off-by: Nuno Das Neves <nunodasneves@xxxxxxxxxxxxxxxxxxx> >>>> --- >>>> Depends on >>>> https://lore.kernel.org/linux-hyperv/1738955002-20821-3-git-send-email-nunodasneves@xxxxxxxxxxxxxxxxxxx/ >>>> >>>> arch/arm64/hyperv/mshyperv.c | 2 ++ >>>> arch/x86/hyperv/hv_init.c | 10 ++++---- >>>> arch/x86/kernel/cpu/mshyperv.c | 24 ++---------------- >>>> drivers/clocksource/hyperv_timer.c | 4 +-- >>>> drivers/hv/Kconfig | 12 +++++++++ >>>> drivers/hv/Makefile | 3 ++- >>>> drivers/hv/hv.c | 10 ++++---- >>>> drivers/hv/hv_common.c | 32 +++++++++++++++++++----- >>>> drivers/hv/vmbus_drv.c | 2 +- >>>> drivers/iommu/hyperv-iommu.c | 4 +-- >>>> include/asm-generic/mshyperv.h | 39 +++++++++++++++++++++++++----- >>>> 11 files changed, 92 insertions(+), 50 deletions(-) >>>> >>>> diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c >>>> index 29fcfd595f48..2265ea5ce5ad 100644 >>>> --- a/arch/arm64/hyperv/mshyperv.c >>>> +++ b/arch/arm64/hyperv/mshyperv.c >>>> @@ -61,6 +61,8 @@ static int __init hyperv_init(void) >>>> ms_hyperv.features, ms_hyperv.priv_high, ms_hyperv.hints, >>>> ms_hyperv.misc_features); >>>> >>>> + hv_identify_partition_type(); >>>> + >>>> ret = hv_common_init(); >>>> if (ret) >>>> return ret; >>>> diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c >>>> index 9be1446f5bd3..ddeb40930bc8 100644 >>>> --- a/arch/x86/hyperv/hv_init.c >>>> +++ b/arch/x86/hyperv/hv_init.c >>>> @@ -90,7 +90,7 @@ static int hv_cpu_init(unsigned int cpu) >>>> return 0; >>>> >>>> hvp = &hv_vp_assist_page[cpu]; >>>> - if (hv_root_partition) { >>>> + if (hv_root_partition()) { >>>> /* >>>> * For root partition we get the hypervisor provided VP assist >>>> * page, instead of allocating a new page. >>>> @@ -242,7 +242,7 @@ static int hv_cpu_die(unsigned int cpu) >>>> >>>> if (hv_vp_assist_page && hv_vp_assist_page[cpu]) { >>>> union hv_vp_assist_msr_contents msr = { 0 }; >>>> - if (hv_root_partition) { >>>> + if (hv_root_partition()) { >>>> /* >>>> * For root partition the VP assist page is mapped to >>>> * hypervisor provided page, and thus we unmap the >>>> @@ -317,7 +317,7 @@ static int hv_suspend(void) >>>> union hv_x64_msr_hypercall_contents hypercall_msr; >>>> int ret; >>>> >>>> - if (hv_root_partition) >>>> + if (hv_root_partition()) >>>> return -EPERM; >>>> >>>> /* >>>> @@ -518,7 +518,7 @@ void __init hyperv_init(void) >>>> rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); >>>> hypercall_msr.enable = 1; >>>> >>>> - if (hv_root_partition) { >>>> + if (hv_root_partition()) { >>>> struct page *pg; >>>> void *src; >>>> >>>> @@ -592,7 +592,7 @@ void __init hyperv_init(void) >>>> * If we're running as root, we want to create our own PCI MSI domain. >>>> * We can't set this in hv_pci_init because that would be too late. >>>> */ >>>> - if (hv_root_partition) >>>> + if (hv_root_partition()) >>>> x86_init.irqs.create_pci_msi_domain = hv_create_pci_msi_domain; >>>> #endif >>>> >>>> diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c >>>> index f285757618fc..4f01f424ea5b 100644 >>>> --- a/arch/x86/kernel/cpu/mshyperv.c >>>> +++ b/arch/x86/kernel/cpu/mshyperv.c >>>> @@ -33,8 +33,6 @@ >>>> #include <asm/numa.h> >>>> #include <asm/svm.h> >>>> >>>> -/* Is Linux running as the root partition? */ >>>> -bool hv_root_partition; >>>> /* Is Linux running on nested Microsoft Hypervisor */ >>>> bool hv_nested; >>>> struct ms_hyperv_info ms_hyperv; >>>> @@ -451,25 +449,7 @@ static void __init ms_hyperv_init_platform(void) >>>> pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n", >>>> ms_hyperv.max_vp_index, ms_hyperv.max_lp_index); >>>> >>>> - /* >>>> - * Check CPU management privilege. >>>> - * >>>> - * To mirror what Windows does we should extract CPU management >>>> - * features and use the ReservedIdentityBit to detect if Linux is the >>>> - * root partition. But that requires negotiating CPU management >>>> - * interface (a process to be finalized). For now, use the privilege >>>> - * flag as the indicator for running as root. >>>> - * >>>> - * Hyper-V should never specify running as root and as a Confidential >>>> - * VM. But to protect against a compromised/malicious Hyper-V trying >>>> - * to exploit root behavior to expose Confidential VM memory, ignore >>>> - * the root partition setting if also a Confidential VM. >>>> - */ >>>> - if ((ms_hyperv.priv_high & HV_CPU_MANAGEMENT) && >>>> - !(ms_hyperv.priv_high & HV_ISOLATION)) { >>>> - hv_root_partition = true; >>>> - pr_info("Hyper-V: running as root partition\n"); >>>> - } >>>> + hv_identify_partition_type(); >>>> >>>> if (ms_hyperv.hints & HV_X64_HYPERV_NESTED) { >>>> hv_nested = true; >>>> @@ -618,7 +598,7 @@ static void __init ms_hyperv_init_platform(void) >>>> >>>> # ifdef CONFIG_SMP >>>> smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu; >>>> - if (hv_root_partition || >>>> + if (hv_root_partition() || >>>> (!ms_hyperv.paravisor_present && hv_isolation_type_snp())) >>>> smp_ops.smp_prepare_cpus = hv_smp_prepare_cpus; >>>> # endif >>>> diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c >>>> index f00019b078a7..09549451dd51 100644 >>>> --- a/drivers/clocksource/hyperv_timer.c >>>> +++ b/drivers/clocksource/hyperv_timer.c >>>> @@ -582,7 +582,7 @@ static void __init hv_init_tsc_clocksource(void) >>>> * mapped. >>>> */ >>>> tsc_msr.as_uint64 = hv_get_msr(HV_MSR_REFERENCE_TSC); >>>> - if (hv_root_partition) >>>> + if (hv_root_partition()) >>>> tsc_pfn = tsc_msr.pfn; >>>> else >>>> tsc_pfn = HVPFN_DOWN(virt_to_phys(tsc_page)); >>>> @@ -627,7 +627,7 @@ void __init hv_remap_tsc_clocksource(void) >>>> if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE)) >>>> return; >>>> >>>> - if (!hv_root_partition) { >>>> + if (!hv_root_partition()) { >>>> WARN(1, "%s: attempt to remap TSC page in guest partition\n", >>>> __func__); >>>> return; >>>> diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig >>>> index 862c47b191af..aac172942f6c 100644 >>>> --- a/drivers/hv/Kconfig >>>> +++ b/drivers/hv/Kconfig >>>> @@ -55,4 +55,16 @@ config HYPERV_BALLOON >>>> help >>>> Select this option to enable Hyper-V Balloon driver. >>>> >>>> +config MSHV_ROOT >>>> + tristate "Microsoft Hyper-V root partition support" >>>> + depends on HYPERV >>>> + depends on !HYPERV_VTL_MODE >>>> + depends on PAGE_SIZE_4KB >>> >>> Add a comment about why PAGE_SIZE_4KB is a requirement, even on >>> arm64 systems that can support guests with larger page sizes. We >>> discussed why in an earlier email thread, but somebody looking at >>> this in the future might wonder. >>> >>>> + default n >>>> + help >>>> + Select this option to enable support for booting and running as root >>>> + partition on Microsoft Hyper-V. >>>> + >>>> + If unsure, say N. >>>> + >>> >>> One thing to keep in mind: Sometimes people build kernels with all >>> config options set to "Y". We want to make sure that if someone does >>> that, the kernel will still run in a non-Hyper-V environment. We had this >>> problem with CONFIG_HYPERV_VTL_MODE=y, where a kernel built with >>> that wouldn't run elsewhere, and that had to be fixed. I don't think the >>> changes in this patch cause a problem in that regard, but it is something >>> to keep in mind for the future. >>> >>> As I see it, setting CONFIG_MSHV_ROOT=y (or =m) just adds code to >>> the kernel image or modules list, and enables runtime detection of >>> whether the kernel is actually in the root partition. If not actually in the >>> root partition, the behavior is normal guest behavior. I think that is all good. >>> >> Yes, agreed. The assumption we are working under is that enabling >> CONFIG_MSHV_ROOT >> doesn't break any normal guest or non-Hyper-V scenarios. >> >> Of course it's hard to always be certain that our code doesn't break some other >> config option at runtime, but we fix that whenever we see it (or exclude the >> combination via Kconfig). >> >>>> endmenu >>>> diff --git a/drivers/hv/Makefile b/drivers/hv/Makefile >>>> index 9afcabb3fbd2..2b8dc954b350 100644 >>>> --- a/drivers/hv/Makefile >>>> +++ b/drivers/hv/Makefile >>>> @@ -13,4 +13,5 @@ hv_vmbus-$(CONFIG_HYPERV_TESTING) += hv_debugfs.o >>>> hv_utils-y := hv_util.o hv_kvp.o hv_snapshot.o hv_utils_transport.o >>>> >>>> # Code that must be built-in >>>> -obj-$(subst m,y,$(CONFIG_HYPERV)) += hv_common.o hv_proc.o >>>> +obj-$(subst m,y,$(CONFIG_HYPERV)) += hv_common.o >>>> +obj-$(subst m,y,$(CONFIG_MSHV_ROOT)) += hv_proc.o >>> >>> OK, so hv_proc.o is always built-in, regardless of whether >>> CONFIG_MSHV_ROOT=y or =m. I think that makes sense. The functions in >>> hv_proc.c are called somewhere in the middle of the kernel boot process, >>> and I'm unsure if the module loading mechanism is fully set up at the point >>> the functions are needed. This approach avoids any risk of not being able >>> to load the module. Presumably still-to-be-added code for the root partition >>> could be built as a module (though see my comment in the commit message). >>> >> >> Yep, that was the idea. >> >>>> diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c >>>> index 36d9ba097ff5..93d82382351c 100644 >>>> --- a/drivers/hv/hv.c >>>> +++ b/drivers/hv/hv.c >>>> @@ -144,7 +144,7 @@ int hv_synic_alloc(void) >>>> * Synic message and event pages are allocated by paravisor. >>>> * Skip these pages allocation here. >>>> */ >>>> - if (!ms_hyperv.paravisor_present && !hv_root_partition) { >>>> + if (!ms_hyperv.paravisor_present && !hv_root_partition()) { >>>> hv_cpu->synic_message_page = >>>> (void *)get_zeroed_page(GFP_ATOMIC); >>>> if (!hv_cpu->synic_message_page) { >>>> @@ -272,7 +272,7 @@ void hv_synic_enable_regs(unsigned int cpu) >>>> simp.as_uint64 = hv_get_msr(HV_MSR_SIMP); >>>> simp.simp_enabled = 1; >>>> >>>> - if (ms_hyperv.paravisor_present || hv_root_partition) { >>>> + if (ms_hyperv.paravisor_present || hv_root_partition()) { >>>> /* Mask out vTOM bit. ioremap_cache() maps decrypted */ >>>> u64 base = (simp.base_simp_gpa << HV_HYP_PAGE_SHIFT) & >>>> ~ms_hyperv.shared_gpa_boundary; >>>> @@ -291,7 +291,7 @@ void hv_synic_enable_regs(unsigned int cpu) >>>> siefp.as_uint64 = hv_get_msr(HV_MSR_SIEFP); >>>> siefp.siefp_enabled = 1; >>>> >>>> - if (ms_hyperv.paravisor_present || hv_root_partition) { >>>> + if (ms_hyperv.paravisor_present || hv_root_partition()) { >>>> /* Mask out vTOM bit. ioremap_cache() maps decrypted */ >>>> u64 base = (siefp.base_siefp_gpa << HV_HYP_PAGE_SHIFT) & >>>> ~ms_hyperv.shared_gpa_boundary; >>>> @@ -367,7 +367,7 @@ void hv_synic_disable_regs(unsigned int cpu) >>>> * addresses. >>>> */ >>>> simp.simp_enabled = 0; >>>> - if (ms_hyperv.paravisor_present || hv_root_partition) { >>>> + if (ms_hyperv.paravisor_present || hv_root_partition()) { >>>> iounmap(hv_cpu->synic_message_page); >>>> hv_cpu->synic_message_page = NULL; >>>> } else { >>>> @@ -379,7 +379,7 @@ void hv_synic_disable_regs(unsigned int cpu) >>>> siefp.as_uint64 = hv_get_msr(HV_MSR_SIEFP); >>>> siefp.siefp_enabled = 0; >>>> >>>> - if (ms_hyperv.paravisor_present || hv_root_partition) { >>>> + if (ms_hyperv.paravisor_present || hv_root_partition()) { >>>> iounmap(hv_cpu->synic_event_page); >>>> hv_cpu->synic_event_page = NULL; >>>> } else { >>>> diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c >>>> index cb3ea49020ef..d1227e85c5b7 100644 >>>> --- a/drivers/hv/hv_common.c >>>> +++ b/drivers/hv/hv_common.c >>>> @@ -34,8 +34,11 @@ >>>> u64 hv_current_partition_id = HV_PARTITION_ID_SELF; >>>> EXPORT_SYMBOL_GPL(hv_current_partition_id); >>>> >>>> +enum hv_partition_type hv_current_partition_type; >>>> +EXPORT_SYMBOL_GPL(hv_current_partition_type); >>>> + >>>> /* >>>> - * hv_root_partition, ms_hyperv and hv_nested are defined here with other >>>> + * ms_hyperv and hv_nested are defined here with other >>>> * Hyper-V specific globals so they are shared across all architectures and are >>>> * built only when CONFIG_HYPERV is defined. But on x86, >>>> * ms_hyperv_init_platform() is built even when CONFIG_HYPERV is not >>>> @@ -43,9 +46,6 @@ EXPORT_SYMBOL_GPL(hv_current_partition_id); >>>> * here, allowing for an overriding definition in the module containing >>>> * ms_hyperv_init_platform(). >>>> */ >>>> -bool __weak hv_root_partition; >>>> -EXPORT_SYMBOL_GPL(hv_root_partition); >>>> - >>>> bool __weak hv_nested; >>>> EXPORT_SYMBOL_GPL(hv_nested); >>>> >>>> @@ -283,7 +283,7 @@ static void hv_kmsg_dump_register(void) >>>> >>>> static inline bool hv_output_page_exists(void) >>>> { >>>> - return hv_root_partition || IS_ENABLED(CONFIG_HYPERV_VTL_MODE); >>>> + return hv_root_partition() || IS_ENABLED(CONFIG_HYPERV_VTL_MODE); >>>> } >>>> >>>> void __init hv_get_partition_id(void) >>>> @@ -594,7 +594,7 @@ EXPORT_SYMBOL_GPL(hv_setup_dma_ops); >>>> >>>> bool hv_is_hibernation_supported(void) >>>> { >>>> - return !hv_root_partition && acpi_sleep_state_supported(ACPI_STATE_S4); >>>> + return !hv_root_partition() && acpi_sleep_state_supported(ACPI_STATE_S4); >>>> } >>>> EXPORT_SYMBOL_GPL(hv_is_hibernation_supported); >>>> >>>> @@ -683,3 +683,23 @@ u64 __weak hv_tdx_hypercall(u64 control, u64 param1, u64 param2) >>>> return HV_STATUS_INVALID_PARAMETER; >>>> } >>>> EXPORT_SYMBOL_GPL(hv_tdx_hypercall); >>>> + >>>> +void hv_identify_partition_type(void) >>>> +{ >>>> + /* >>>> + * Check partition creation and cpu management privileges >>>> + * >>>> + * Hyper-V should never specify running as root and as a Confidential >>>> + * VM. But to protect against a compromised/malicious Hyper-V trying >>>> + * to exploit root behavior to expose Confidential VM memory, ignore >>>> + * the root partition setting if also a Confidential VM. >>>> + */ >>>> + if ((ms_hyperv.priv_high & HV_CREATE_PARTITIONS) && >>>> + (ms_hyperv.priv_high & HV_CPU_MANAGEMENT) && >>>> + !(ms_hyperv.priv_high & HV_ISOLATION)) { >>>> + hv_current_partition_type = HV_PARTITION_TYPE_ROOT; >>>> + pr_info("Hyper-V: running as root partition\n"); >>>> + } else { >>>> + hv_current_partition_type = HV_PARTITION_TYPE_GUEST; >>>> + } >>> >>> If the flags indicate running in the root partition, but CONFIG_MSHV_ROOT=n, >>> perhaps that should probably be flagged with an error message. I haven't thought >>> through what to do then: Panic, keep running as a normal guest, or something else? >>> >> >> If the kernel is run as root partition with CONFIG_MSHV_ROOT=n, I think it will crash >> or hang at some point later in boot. >> >> How about this: >> >> if ((ms_hyperv.priv_high & HV_CREATE_PARTITIONS) && >> (ms_hyperv.priv_high & HV_CPU_MANAGEMENT) && >> !(ms_hyperv.priv_high & HV_ISOLATION)) { >> pr_info("Hyper-V: running as root partition\n"); >> if (IS_ENABLED(CONFIG_MSHV_ROOT)) >> hv_current_partition_type = HV_PARTITION_TYPE_ROOT; >> else >> pr_crit("Hyper-V: CONFIG_MSHV_ROOT not enabled!\n"); >> } >> >> We could also BUG_ON() since it will almost certainly crash anyway, but maybe just >> letting it continue is ok. > > I'm OK with just continuing, as I don't have any justification for an alternative. > It's a strange situation that should not happen, but it's worthwhile to output > some indication of why things are about to go badly. > Ok, thanks for the comments. Planning to post v2 soon. Nuno > Michael > >> >>>> +} >>>> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c >>>> index 0f6cd44fff29..844eba0429fa 100644 >>>> --- a/drivers/hv/vmbus_drv.c >>>> +++ b/drivers/hv/vmbus_drv.c >>>> @@ -2646,7 +2646,7 @@ static int __init hv_acpi_init(void) >>>> if (!hv_is_hyperv_initialized()) >>>> return -ENODEV; >>>> >>>> - if (hv_root_partition && !hv_nested) >>>> + if (hv_root_partition() && !hv_nested) >>>> return 0; >>>> >>>> /* >>>> diff --git a/drivers/iommu/hyperv-iommu.c b/drivers/iommu/hyperv-iommu.c >>>> index 2a86aa5d54c6..53e4b37716af 100644 >>>> --- a/drivers/iommu/hyperv-iommu.c >>>> +++ b/drivers/iommu/hyperv-iommu.c >>>> @@ -130,7 +130,7 @@ static int __init hyperv_prepare_irq_remapping(void) >>>> x86_init.hyper.msi_ext_dest_id()) >>>> return -ENODEV; >>>> >>>> - if (hv_root_partition) { >>>> + if (hv_root_partition()) { >>>> name = "HYPERV-ROOT-IR"; >>>> ops = &hyperv_root_ir_domain_ops; >>>> } else { >>>> @@ -151,7 +151,7 @@ static int __init hyperv_prepare_irq_remapping(void) >>>> return -ENOMEM; >>>> } >>>> >>>> - if (hv_root_partition) >>>> + if (hv_root_partition()) >>>> return 0; /* The rest is only relevant to guests */ >>>> >>>> /* >>>> diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h >>>> index 7adc10a4fa3e..6f898792fb51 100644 >>>> --- a/include/asm-generic/mshyperv.h >>>> +++ b/include/asm-generic/mshyperv.h >>>> @@ -28,6 +28,11 @@ >>>> >>>> #define VTPM_BASE_ADDRESS 0xfed40000 >>>> >>>> +enum hv_partition_type { >>>> + HV_PARTITION_TYPE_GUEST, >>>> + HV_PARTITION_TYPE_ROOT, >>>> +}; >>>> + >>>> struct ms_hyperv_info { >>>> u32 features; >>>> u32 priv_high; >>>> @@ -59,6 +64,7 @@ struct ms_hyperv_info { >>>> extern struct ms_hyperv_info ms_hyperv; >>>> extern bool hv_nested; >>>> extern u64 hv_current_partition_id; >>>> +extern enum hv_partition_type hv_current_partition_type; >>>> >>>> extern void * __percpu *hyperv_pcpu_input_arg; >>>> extern void * __percpu *hyperv_pcpu_output_arg; >>>> @@ -190,8 +196,6 @@ void hv_remove_crash_handler(void); >>>> extern int vmbus_interrupt; >>>> extern int vmbus_irq; >>>> >>>> -extern bool hv_root_partition; >>>> - >>>> #if IS_ENABLED(CONFIG_HYPERV) >>>> /* >>>> * Hypervisor's notion of virtual processor ID is different from >>>> @@ -213,15 +217,12 @@ void __init hv_common_free(void); >>>> void __init ms_hyperv_late_init(void); >>>> int hv_common_cpu_init(unsigned int cpu); >>>> int hv_common_cpu_die(unsigned int cpu); >>>> +void hv_identify_partition_type(void); >>>> >>>> void *hv_alloc_hyperv_page(void); >>>> void *hv_alloc_hyperv_zeroed_page(void); >>>> void hv_free_hyperv_page(void *addr); >>>> >>>> -int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages); >>>> -int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id); >>>> -int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags); >>>> - >>>> /** >>>> * hv_cpu_number_to_vp_number() - Map CPU to VP. >>>> * @cpu_number: CPU number in Linux terms >>>> @@ -309,6 +310,7 @@ void hyperv_cleanup(void); >>>> bool hv_query_ext_cap(u64 cap_query); >>>> void hv_setup_dma_ops(struct device *dev, bool coherent); >>>> #else /* CONFIG_HYPERV */ >>>> +static inline void hv_identify_partition_type(void) {} >>>> static inline bool hv_is_hyperv_initialized(void) { return false; } >>>> static inline bool hv_is_hibernation_supported(void) { return false; } >>>> static inline void hyperv_cleanup(void) {} >>>> @@ -320,4 +322,29 @@ static inline enum hv_isolation_type hv_get_isolation_type(void) >>>> } >>>> #endif /* CONFIG_HYPERV */ >>>> >>>> +#if IS_ENABLED(CONFIG_MSHV_ROOT) >>>> +static inline bool hv_root_partition(void) >>>> +{ >>>> + return hv_current_partition_type == HV_PARTITION_TYPE_ROOT; >>> >>> Nit: There's an extra space character after "return". >>> >> >> Fixed for next version, thanks. >> >>>> +} >>>> +int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages); >>>> +int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id); >>>> +int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags); >>>> + >>>> +#else /* CONFIG_MSHV_ROOT */ >>>> +static inline bool hv_root_partition(void) { return false; } >>>> +static inline int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages) >>>> +{ >>>> + return hv_result(U64_MAX); >>>> +} >>>> +static inline int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id) >>>> +{ >>>> + return hv_result(U64_MAX); >>>> +} >>>> +static inline int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags) >>>> +{ >>>> + return hv_result(U64_MAX); >>>> +} >>>> +#endif /* CONFIG_MSHV_ROOT */ >>>> + >>>> #endif >>>> -- >>>> 2.34.1
