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    SubjectRE: [PATCH v6 06/16] x86/hyperv: extract partition ID from Microsoft Hypervisor if necessary
    Date
    From: Wei Liu <wei.liu@kernel.org> Sent: Wednesday, February 3, 2021 7:04 AM
    >
    > We will need the partition ID for executing some hypercalls later.
    >
    > Signed-off-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
    > Co-Developed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
    > Signed-off-by: Wei Liu <wei.liu@kernel.org>
    > ---
    > v6:
    > 1. Use u64 status.
    >
    > v3:
    > 1. Make hv_get_partition_id static.
    > 2. Change code structure a bit.
    > ---
    > arch/x86/hyperv/hv_init.c | 26 ++++++++++++++++++++++++++
    > arch/x86/include/asm/mshyperv.h | 2 ++
    > include/asm-generic/hyperv-tlfs.h | 6 ++++++
    > 3 files changed, 34 insertions(+)
    >
    > diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
    > index 6f4cb40e53fe..5b90a7290177 100644
    > --- a/arch/x86/hyperv/hv_init.c
    > +++ b/arch/x86/hyperv/hv_init.c
    > @@ -26,6 +26,9 @@
    > #include <linux/syscore_ops.h>
    > #include <clocksource/hyperv_timer.h>
    >
    > +u64 hv_current_partition_id = ~0ull;
    > +EXPORT_SYMBOL_GPL(hv_current_partition_id);
    > +
    > void *hv_hypercall_pg;
    > EXPORT_SYMBOL_GPL(hv_hypercall_pg);
    >
    > @@ -331,6 +334,24 @@ static struct syscore_ops hv_syscore_ops = {
    > .resume = hv_resume,
    > };
    >
    > +static void __init hv_get_partition_id(void)
    > +{
    > + struct hv_get_partition_id *output_page;
    > + u64 status;
    > + unsigned long flags;
    > +
    > + local_irq_save(flags);
    > + output_page = *this_cpu_ptr(hyperv_pcpu_output_arg);
    > + status = hv_do_hypercall(HVCALL_GET_PARTITION_ID, NULL, output_page);
    > + if ((status & HV_HYPERCALL_RESULT_MASK) != HV_STATUS_SUCCESS) {
    > + /* No point in proceeding if this failed */
    > + pr_err("Failed to get partition ID: %lld\n", status);
    > + BUG();
    > + }
    > + hv_current_partition_id = output_page->partition_id;
    > + local_irq_restore(flags);
    > +}
    > +
    > /*
    > * This function is to be invoked early in the boot sequence after the
    > * hypervisor has been detected.
    > @@ -426,6 +447,11 @@ void __init hyperv_init(void)
    >
    > register_syscore_ops(&hv_syscore_ops);
    >
    > + if (cpuid_ebx(HYPERV_CPUID_FEATURES) & HV_ACCESS_PARTITION_ID)
    > + hv_get_partition_id();
    > +
    > + BUG_ON(hv_root_partition && hv_current_partition_id == ~0ull);
    > +
    > return;
    >
    > remove_cpuhp_state:
    > diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
    > index 62d9390f1ddf..67f5d35a73d3 100644
    > --- a/arch/x86/include/asm/mshyperv.h
    > +++ b/arch/x86/include/asm/mshyperv.h
    > @@ -78,6 +78,8 @@ extern void *hv_hypercall_pg;
    > extern void __percpu **hyperv_pcpu_input_arg;
    > extern void __percpu **hyperv_pcpu_output_arg;
    >
    > +extern u64 hv_current_partition_id;
    > +
    > static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
    > {
    > u64 input_address = input ? virt_to_phys(input) : 0;
    > diff --git a/include/asm-generic/hyperv-tlfs.h b/include/asm-generic/hyperv-tlfs.h
    > index e6903589a82a..87b1a79b19eb 100644
    > --- a/include/asm-generic/hyperv-tlfs.h
    > +++ b/include/asm-generic/hyperv-tlfs.h
    > @@ -141,6 +141,7 @@ struct ms_hyperv_tsc_page {
    > #define HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX 0x0013
    > #define HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX 0x0014
    > #define HVCALL_SEND_IPI_EX 0x0015
    > +#define HVCALL_GET_PARTITION_ID 0x0046
    > #define HVCALL_GET_VP_REGISTERS 0x0050
    > #define HVCALL_SET_VP_REGISTERS 0x0051
    > #define HVCALL_POST_MESSAGE 0x005c
    > @@ -407,6 +408,11 @@ struct hv_tlb_flush_ex {
    > u64 gva_list[];
    > } __packed;
    >
    > +/* HvGetPartitionId hypercall (output only) */
    > +struct hv_get_partition_id {
    > + u64 partition_id;
    > +} __packed;
    > +
    > /* HvRetargetDeviceInterrupt hypercall */
    > union hv_msi_entry {
    > u64 as_uint64;
    > --
    > 2.20.1

    Reviewed-by: Michael Kelley <mikelley@microsoft.com>

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