Wei Liu <wei.liu@xxxxxxxxxx> writes:
> We will need the partition ID for executing some hypercalls later.
>
> Signed-off-by: Lillian Grassin-Drake <ligrassi@xxxxxxxxxxxxx>
> Co-Developed-by: Sunil Muthuswamy <sunilmut@xxxxxxxxxxxxx>
> Signed-off-by: Wei Liu <wei.liu@xxxxxxxxxx>
> ---
> 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 7a2e37f025b0..73b0fb851f76 100644
> --- a/arch/x86/hyperv/hv_init.c
> +++ b/arch/x86/hyperv/hv_init.c
> @@ -30,6 +30,9 @@
> bool hv_root_partition;
> EXPORT_SYMBOL_GPL(hv_root_partition);
>
> +u64 hv_current_partition_id;
> +EXPORT_SYMBOL_GPL(hv_current_partition_id);
> +
> void *hv_hypercall_pg;
> EXPORT_SYMBOL_GPL(hv_hypercall_pg);
>
> @@ -335,6 +338,26 @@ static struct syscore_ops hv_syscore_ops = {
> .resume = hv_resume,
> };
>
> +void __init hv_get_partition_id(void)
> +{
> + struct hv_get_partition_id *output_page;
> + u16 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) &
> + HV_HYPERCALL_RESULT_MASK;
> + if (status != HV_STATUS_SUCCESS)
> + pr_err("Failed to get partition ID: %d\n", status);
> + else
> + hv_current_partition_id = output_page->partition_id;
Nit: I'd suggest we simplify this to:
if (status != HV_STATUS_SUCCESS) {
pr_err("Failed to get partition ID: %d\n", status);
BUG();
}
hv_current_partition_id = output_page->partition_id;
and drop BUG_ON() below;
> + local_irq_restore(flags);
> +
> + /* No point in proceeding if this failed */
> + BUG_ON(status != HV_STATUS_SUCCESS);
> +}
> +
> /*
> * This function is to be invoked early in the boot sequence after the
> * hypervisor has been detected.
> @@ -430,6 +453,9 @@ void __init hyperv_init(void)
>
> register_syscore_ops(&hv_syscore_ops);
>
> + if (hv_root_partition)
> + hv_get_partition_id();
> +
We don't seem to check that the partition has AccessPartitionId
privilege. While I guess that root partitions always have it, I'd
suggest we write this as:
if (cpuid_ebx(HYPERV_CPUID_FEATURES) & HV_ACCESS_PARTITION_ID)
hv_get_partition_id();
BUG_ON(hv_root_partition && !hv_current_partition_id);
for correctness. Also, we need to make sure '0' is not a valid partition
id and use e.g. -1 otherwise.
> 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;
--
Vitaly
