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Subject[RFC 3/6] x86/hyper-v: allocate and use hv_vp_assist_pages
Date
These pages are going to be used for Enlightened VMCS support in KVM.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
arch/x86/hyperv/hv_init.c | 35 ++++++++++++++++++++++++++++++++++-
arch/x86/include/asm/mshyperv.h | 1 +
2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 189a398290db..a5eb0a89e299 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -85,6 +85,9 @@ EXPORT_SYMBOL_GPL(hyperv_cs);
u32 *hv_vp_index;
EXPORT_SYMBOL_GPL(hv_vp_index);

+struct hv_vp_assist_page **hv_vp_assist_page;
+EXPORT_SYMBOL_GPL(hv_vp_assist_page);
+
u32 hv_max_vp_index;

static int hv_cpu_init(unsigned int cpu)
@@ -98,6 +101,31 @@ static int hv_cpu_init(unsigned int cpu)
if (msr_vp_index > hv_max_vp_index)
hv_max_vp_index = msr_vp_index;

+ if (!hv_vp_assist_page[smp_processor_id()])
+ hv_vp_assist_page[smp_processor_id()] =
+ __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
+
+ if (hv_vp_assist_page[smp_processor_id()]) {
+ u64 val;
+
+ val = vmalloc_to_pfn(hv_vp_assist_page[smp_processor_id()]);
+ val = (val << HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT) |
+ HV_X64_MSR_VP_ASSIST_PAGE_ENABLE;
+
+ wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, val);
+ }
+
+ return 0;
+}
+
+static int hv_cpu_die(unsigned int cpu)
+{
+ if (hv_vp_assist_page[cpu]) {
+ wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, 0);
+ vfree(hv_vp_assist_page[cpu]);
+ hv_vp_assist_page[cpu] = NULL;
+ }
+
return 0;
}

@@ -122,8 +150,13 @@ void hyperv_init(void)
if (!hv_vp_index)
return;

+ hv_vp_assist_page = kcalloc(num_possible_cpus(),
+ sizeof(*hv_vp_assist_page), GFP_KERNEL);
+ if (!hv_vp_assist_page)
+ return;
+
if (cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online",
- hv_cpu_init, NULL) < 0)
+ hv_cpu_init, hv_cpu_die) < 0)
goto free_vp_index;

/*
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 5400add2885b..245e08a2e48d 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -291,6 +291,7 @@ static inline u64 hv_do_rep_hypercall(u16 code, u16 rep_count, u16 varhead_size,
*/
extern u32 *hv_vp_index;
extern u32 hv_max_vp_index;
+extern struct hv_vp_assist_page **hv_vp_assist_page;

/**
* hv_cpu_number_to_vp_number() - Map CPU to VP.
--
2.14.3
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