x86/hyperv: extract partition ID from Microsoft Hypervisor if necessary

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>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210203150435.27941-7-wei.liu@kernel.org

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index a73f4db31870672627dd42a87f714ea9ad1cf7ff..612c555fb9aa7411f5c87c16d27e643d351f7024 100644 (file)
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -29,6 +29,8 @@
 #include <clocksource/hyperv_timer.h>
 
 int hyperv_init_cpuhp;
+u64 hv_current_partition_id = ~0ull;
+EXPORT_SYMBOL_GPL(hv_current_partition_id);
 
 void *hv_hypercall_pg;
 EXPORT_SYMBOL_GPL(hv_hypercall_pg);
@@ -354,6 +356,24 @@ static void __init hv_stimer_setup_percpu_clockev(void)
                old_setup_percpu_clockev();
 }
 
+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.
@@ -454,6 +474,12 @@ void __init hyperv_init(void)
        register_syscore_ops(&hv_syscore_ops);
 
        hyperv_init_cpuhp = cpuhp;
+
+       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 ef06cdac8444dc365848955848c3e9cda318fa83..b8324202d85012ef96ff9cb7bd488512738b44a6 100644 (file)
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -80,6 +80,8 @@ 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 e232ddcb0a2d0529e3029fe559f111b114000f26..ba96bcb5c657e1de87c558d97f4bd41798107896 100644 (file)
--- a/include/asm-generic/hyperv-tlfs.h
+++ b/include/asm-generic/hyperv-tlfs.h
@@ -142,6 +142,7 @@ 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
@@ -408,6 +409,11 @@ 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;