x86/hyper-v: Fix the circular dependency in IPI enlightenment

The IPI hypercalls depend on being able to map the Linux notion of CPU ID
to the hypervisor's notion of the CPU ID. The array hv_vp_index[] provides
this mapping. Code for populating this array depends on the IPI functionality.
Break this circular dependency.

[ tglx: Use a proper define instead of '-1' with a u32 variable as pointed
  	out by Vitaly ]

Fixes: 68bb7bfb7985 ("X86/Hyper-V: Enable IPI enlightenments")
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Cc: gregkh@linuxfoundation.org
Cc: devel@linuxdriverproject.org
Cc: olaf@aepfle.de
Cc: apw@canonical.com
Cc: jasowang@redhat.com
Cc: hpa@zytor.com
Cc: sthemmin@microsoft.com
Cc: Michael.H.Kelley@microsoft.com
Cc: vkuznets@redhat.com
Link: https://lkml.kernel.org/r/20180703230155.15160-1-kys@linuxonhyperv.com

diff --git a/arch/x86/hyperv/hv_apic.c b/arch/x86/hyperv/hv_apic.c
index f68855499391f4637532fa0de4c95ca844e6563e..40233836565118f4fb60239ded1fc09aabe34cf1 100644 (file)
--- a/arch/x86/hyperv/hv_apic.c
+++ b/arch/x86/hyperv/hv_apic.c
@@ -114,6 +114,8 @@ static bool __send_ipi_mask_ex(const struct cpumask *mask, int vector)
                ipi_arg->vp_set.format = HV_GENERIC_SET_SPARSE_4K;
                nr_bank = cpumask_to_vpset(&(ipi_arg->vp_set), mask);
        }
+       if (nr_bank < 0)
+               goto ipi_mask_ex_done;
        if (!nr_bank)
                ipi_arg->vp_set.format = HV_GENERIC_SET_ALL;
 
@@ -158,6 +160,9 @@ static bool __send_ipi_mask(const struct cpumask *mask, int vector)
 
        for_each_cpu(cur_cpu, mask) {
                vcpu = hv_cpu_number_to_vp_number(cur_cpu);
+               if (vcpu == VP_INVAL)
+                       goto ipi_mask_done;
+
                /*
                 * This particular version of the IPI hypercall can
                 * only target upto 64 CPUs.

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 4c431e1c1effc42ade651f9a69c3e06136827e17..1ff420217298edf88648d35b56cefb73b8beb788 100644 (file)
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -265,7 +265,7 @@ void __init hyperv_init(void)
 {
        u64 guest_id, required_msrs;
        union hv_x64_msr_hypercall_contents hypercall_msr;
-       int cpuhp;
+       int cpuhp, i;
 
        if (x86_hyper_type != X86_HYPER_MS_HYPERV)
                return;
@@ -293,6 +293,9 @@ void __init hyperv_init(void)
        if (!hv_vp_index)
                return;
 
+       for (i = 0; i < num_possible_cpus(); i++)
+               hv_vp_index[i] = VP_INVAL;
+
        hv_vp_assist_page = kcalloc(num_possible_cpus(),
                                    sizeof(*hv_vp_assist_page), GFP_KERNEL);
        if (!hv_vp_assist_page) {

diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 3cd14311edfad6d04c5ea382b2b6845f66a9d6f8..5a7375ed5f7cd80ca9925f05d422a9090e3602be 100644 (file)
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -9,6 +9,8 @@
 #include <asm/hyperv-tlfs.h>
 #include <asm/nospec-branch.h>
 
+#define VP_INVAL       U32_MAX
+
 struct ms_hyperv_info {
        u32 features;
        u32 misc_features;
@@ -20,7 +22,6 @@ struct ms_hyperv_info {
 
 extern struct ms_hyperv_info ms_hyperv;
 
-
 /*
  * Generate the guest ID.
  */
@@ -281,6 +282,8 @@ static inline int cpumask_to_vpset(struct hv_vpset *vpset,
         */
        for_each_cpu(cpu, cpus) {
                vcpu = hv_cpu_number_to_vp_number(cpu);
+               if (vcpu == VP_INVAL)
+                       return -1;
                vcpu_bank = vcpu / 64;
                vcpu_offset = vcpu % 64;
                __set_bit(vcpu_offset, (unsigned long *)