[PATCH 16/28] Drivers: hv: Setup a mapping for Hyper-V's notion cpu ID

K. Y. Srinivasan
2012-12-01T14:25:54Z

On win8 (ws2012), incoming vmbus interrupt load can be spread across all
available VCPUs in the guest. On a per-channel basis, the interrupts can
be bound to specific CPUs. The Linux notion of cpu ID may be different
from that of the hypervisor's. Setup a mapping structure.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
---
drivers/hv/hv.c | 11 +++++++++++
drivers/hv/hyperv_vmbus.h | 10 ++++++++++
2 files changed, 21 insertions(+), 0 deletions(-)

diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index dd0af89..76304a6 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -137,6 +137,8 @@ int hv_init(void)
memset(hv_context.synic_event_page, 0, sizeof(void *) * NR_CPUS);
memset(hv_context.synic_message_page, 0,
sizeof(void *) * NR_CPUS);
+ memset(hv_context.vp_index, 0,
+ sizeof(int) * NR_CPUS);

max_leaf = query_hypervisor_info();

@@ -296,6 +298,7 @@ void hv_synic_init(void *irqarg)
union hv_synic_siefp siefp;
union hv_synic_sint shared_sint;
union hv_synic_scontrol sctrl;
+ u64 vp_index;

u32 irq_vector = *((u32 *)(irqarg));
int cpu = smp_processor_id();
@@ -355,6 +358,14 @@ void hv_synic_init(void *irqarg)
wrmsrl(HV_X64_MSR_SCONTROL, sctrl.as_uint64);

hv_context.synic_initialized = true;
+
+ /*
+ * Setup the mapping between Hyper-V's notion
+ * of cpuid and Linux' notion of cpuid.
+ * This array will be indexed using Linux cpuid.
+ */
+ rdmsrl(HV_X64_MSR_VP_INDEX, vp_index);
+ hv_context.vp_index[cpu] = (u32)vp_index;
return;

cleanup:
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 1bc7500..6bbc197 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -502,6 +502,16 @@ struct hv_context {

void *synic_message_page[NR_CPUS];
void *synic_event_page[NR_CPUS];
+ /*
+ * Hypervisor's notion of virtual processor ID is different from
+ * Linux' notion of CPU ID. This information can only be retrieved
+ * in the context of the calling CPU. Setup a map for easy access
+ * to this information:
+ *
+ * vp_index[a] is the Hyper-V's processor ID corresponding to
+ * Linux cpuid 'a'.
+ */
+ u32 vp_index[NR_CPUS];
};

extern struct hv_context hv_context;
--
1.7.4.1