[PATCH v3 10/17] x86/hyperv: implement and use hv_smp_prepare_cpus

Wei Liu
2020-11-24T17:08:59Z

Microsoft Hypervisor requires the root partition to make a few
hypercalls to setup application processors before they can be used.

Signed-off-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Co-Developed-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
Co-Developed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
---
CPU hotplug and unplug is not yet supported in this setup, so those
paths remain untouched.

v3: Always call native SMP preparation function.
---
arch/x86/kernel/cpu/mshyperv.c | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)

diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index f0b8c702c858..956007d2bf0d 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -31,6 +31,7 @@
#include <asm/reboot.h>
#include <asm/nmi.h>
#include <clocksource/hyperv_timer.h>
+#include <asm/numa.h>

/* Is Linux running as the root partition? */
bool hv_root_partition;
@@ -212,6 +213,32 @@ static void __init hv_smp_prepare_boot_cpu(void)
hv_init_spinlocks();
#endif
}
+
+static void __init hv_smp_prepare_cpus(unsigned int max_cpus)
+{
+#ifdef CONFIG_X86_64
+ int i;
+ int ret;
+#endif
+
+ native_smp_prepare_cpus(max_cpus);
+
+#ifdef CONFIG_X86_64
+ for_each_present_cpu(i) {
+ if (i == 0)
+ continue;
+ ret = hv_call_add_logical_proc(numa_cpu_node(i), i, cpu_physical_id(i));
+ BUG_ON(ret);
+ }
+
+ for_each_present_cpu(i) {
+ if (i == 0)
+ continue;
+ ret = hv_call_create_vp(numa_cpu_node(i), hv_current_partition_id, i, i);
+ BUG_ON(ret);
+ }
+#endif
+}
#endif

static void __init ms_hyperv_init_platform(void)
@@ -368,6 +395,8 @@ 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)
+ smp_ops.smp_prepare_cpus = hv_smp_prepare_cpus;
# endif

/*
--
2.20.1