Virtual Processor Assist Pages usage allows us to do optimized EOI
processing for APIC, enable Enlightened VMCS support in KVM and more.
struct hv_vp_assist_page is defined according to the Hyper-V TLFS v5.0b.
Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/x86/hyperv/hv_init.c | 43 +++++++++++++++++++++++++++++++++++---
arch/x86/include/asm/hyperv-tlfs.h | 13 ++++++++++++
arch/x86/include/asm/mshyperv.h | 13 ++++++++++++
3 files changed, 66 insertions(+), 3 deletions(-)
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 4b82bc206929..cfecc2272f2d 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -88,11 +88,15 @@ 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)
{
u64 msr_vp_index;
+ struct hv_vp_assist_page **hvp = &hv_vp_assist_page[smp_processor_id()];
hv_get_vp_index(msr_vp_index);
@@ -101,6 +105,22 @@ 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)
+ return 0;
+
+ if (!*hvp)
+ *hvp = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
+
+ if (*hvp) {
+ u64 val;
+
+ val = vmalloc_to_pfn(*hvp);
+ 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;
}
@@ -198,6 +218,9 @@ static int hv_cpu_die(unsigned int cpu)
struct hv_reenlightenment_control re_ctrl;
unsigned int new_cpu;
+ if (hv_vp_assist_page && hv_vp_assist_page[cpu])
+ wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, 0);
+
if (hv_reenlightenment_cb == NULL)
return 0;
@@ -224,6 +247,7 @@ void hyperv_init(void)
{
u64 guest_id, required_msrs;
union hv_x64_msr_hypercall_contents hypercall_msr;
+ int cpuhp;
if (x86_hyper_type != X86_HYPER_MS_HYPERV)
return;
@@ -241,9 +265,17 @@ void hyperv_init(void)
if (!hv_vp_index)
return;
- if (cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online",
- hv_cpu_init, hv_cpu_die) < 0)
+ hv_vp_assist_page = kcalloc(num_possible_cpus(),
+ sizeof(*hv_vp_assist_page), GFP_KERNEL);
+ if (!hv_vp_assist_page) {
+ ms_hyperv.hints &= ~HV_X64_ENLIGHTENED_VMCS_RECOMMENDED;
goto free_vp_index;
+ }
+
+ cpuhp = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online",
+ hv_cpu_init, hv_cpu_die);
+ if (cpuhp < 0)
+ goto free_vp_assist_page;
/*
* Setup the hypercall page and enable hypercalls.
@@ -256,7 +288,7 @@ void hyperv_init(void)
hv_hypercall_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_RX);
if (hv_hypercall_pg == NULL) {
wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
- goto free_vp_index;
+ goto remove_cpuhp_state;
}
rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
@@ -304,6 +336,11 @@ void hyperv_init(void)
return;
+remove_cpuhp_state:
+ cpuhp_remove_state(cpuhp);
+free_vp_assist_page:
+ kfree(hv_vp_assist_page);
+ hv_vp_assist_page = NULL;
free_vp_index:
kfree(hv_vp_index);
hv_vp_index = NULL;
diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
index acdec9a957db..41eac22db5e3 100644
--- a/arch/x86/include/asm/hyperv-tlfs.h
+++ b/arch/x86/include/asm/hyperv-tlfs.h
@@ -163,6 +163,9 @@
/* Recommend using the newer ExProcessorMasks interface */
#define HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED (1 << 11)
+/* Recommend using enlightened VMCS */
+#define HV_X64_ENLIGHTENED_VMCS_RECOMMENDED (1 << 14)
+
/*
* Crash notification flag.
*/
@@ -476,6 +479,16 @@ struct hv_timer_message_payload {
__u64 delivery_time; /* When the message was delivered */
};
+/* Define virtual processor assist page structure. */
+struct hv_vp_assist_page {
+ __u32 apic_assist;
+ __u32 reserved;
+ __u64 vtl_control[2];
+ __u64 nested_enlightenments_control[2];
+ __u32 enlighten_vmentry;
+ __u64 current_nested_vmcs;
+};
+
#define HV_STIMER_ENABLE (1ULL << 0)
#define HV_STIMER_PERIODIC (1ULL << 1)
#define HV_STIMER_LAZY (1ULL << 2)
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 38cfbe9a5794..3f162353f180 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -218,6 +218,15 @@ 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;
+
+static inline struct hv_vp_assist_page *hv_get_vp_assist_page(unsigned int cpu)
+{
+ if (!hv_vp_assist_page)
+ return NULL;
+
+ return hv_vp_assist_page[cpu];
+}
/**
* hv_cpu_number_to_vp_number() - Map CPU to VP.
@@ -254,6 +263,10 @@ static inline void hyperv_setup_mmu_ops(void) {}
static inline void set_hv_tscchange_cb(void (*cb)(void)) {}
static inline void clear_hv_tscchange_cb(void) {}
static inline void hyperv_stop_tsc_emulation(void) {};
+static inline struct hv_vp_assist_page *hv_get_vp_assist_page(unsigned int cpu)
+{
+ return NULL;
+}
#endif /* CONFIG_HYPERV */
#ifdef CONFIG_HYPERV_TSCPAGE
--
2.14.3
