[PATCH v4 09/10] x86/hyper-v: support extended CPU ranges for TLB flush hypercalls

Vitaly Kuznetsov
2017-05-24T12:05:06Z

Hyper-V hosts may support more than 64 vCPUs, we need to use
HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX/LIST_EX hypercalls in this
case.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: K. Y. Srinivasan <kys@microsoft.com>
Tested-by: Simon Xiao <sixiao@microsoft.com>
Tested-by: Srikanth Myakam <v-srm@microsoft.com>
---
arch/x86/hyperv/mmu.c | 149 ++++++++++++++++++++++++++++++++++++-
arch/x86/include/uapi/asm/hyperv.h | 10 +++
2 files changed, 157 insertions(+), 2 deletions(-)

diff --git a/arch/x86/hyperv/mmu.c b/arch/x86/hyperv/mmu.c
index e3ab9b9..c9cecb3 100644
--- a/arch/x86/hyperv/mmu.c
+++ b/arch/x86/hyperv/mmu.c
@@ -15,8 +15,57 @@ struct hv_flush_pcpu {
__u64 gva_list[];
};

+/* HvFlushVirtualAddressSpaceEx, HvFlushVirtualAddressListEx hypercalls */
+struct hv_flush_pcpu_ex {
+ __u64 address_space;
+ __u64 flags;
+ struct {
+ __u64 format;
+ __u64 valid_bank_mask;
+ __u64 bank_contents[];
+ } hv_vp_set;
+ __u64 gva_list[];
+};
+
static struct hv_flush_pcpu __percpu *pcpu_flush;

+static struct hv_flush_pcpu_ex __percpu *pcpu_flush_ex;
+
+static inline int cpumask_to_vp_set(struct hv_flush_pcpu_ex *flush,
+ const struct cpumask *cpus)
+{
+ int cur_bank, cpu, vcpu, nr_bank = 0;
+ bool has_cpus;
+
+ /*
+ * We can't be sure that translated vcpu numbers will always be
+ * in ascending order, so iterate over all possible banks and
+ * check all vcpus in it instead.
+ */
+ for (cur_bank = 0; cur_bank < ms_hyperv.max_vp_index/64; cur_bank++) {
+ has_cpus = false;
+ for_each_cpu(cpu, cpus) {
+ vcpu = hv_cpu_number_to_vp_number(cpu);
+ if (vcpu/64 != cur_bank)
+ continue;
+ if (!has_cpus) {
+ flush->hv_vp_set.valid_bank_mask |=
+ 1 << vcpu / 64;
+ flush->hv_vp_set.bank_contents[nr_bank] =
+ 1 << vcpu % 64;
+ has_cpus = true;
+ } else {
+ flush->hv_vp_set.bank_contents[nr_bank] |=
+ 1 << vcpu % 64;
+ }
+ }
+ if (has_cpus)
+ nr_bank++;
+ }
+
+ return nr_bank;
+}
+
static void hyperv_flush_tlb_others(const struct cpumask *cpus,
struct mm_struct *mm, unsigned long start,
unsigned long end)
@@ -102,16 +151,112 @@ static void hyperv_flush_tlb_others(const struct cpumask *cpus,
native_flush_tlb_others(cpus, mm, start, end);
}

+static void hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
+ struct mm_struct *mm,
+ unsigned long start,
+ unsigned long end)
+{
+ struct hv_flush_pcpu_ex *flush;
+ unsigned long cur, flags;
+ u64 status = -1ULL;
+ int nr_bank = 0, max_gvas, gva_n;
+
+ if (!pcpu_flush_ex || !hv_hypercall_pg)
+ goto do_native;
+
+ if (cpumask_empty(cpus))
+ return;
+
+ local_irq_save(flags);
+
+ flush = this_cpu_ptr(pcpu_flush_ex);
+
+ if (mm) {
+ flush->address_space = virt_to_phys(mm->pgd);
+ flush->flags = 0;
+ } else {
+ flush->address_space = 0;
+ flush->flags = HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES;
+ }
+
+ flush->hv_vp_set.valid_bank_mask = 0;
+
+ if (cpumask_equal(cpus, cpu_present_mask)) {
+ flush->hv_vp_set.format = HV_GENERIC_SET_ALL;
+ flush->flags |= HV_FLUSH_ALL_PROCESSORS;
+ } else {
+ flush->hv_vp_set.format = HV_GENERIC_SET_SPARCE_4K;
+ nr_bank = cpumask_to_vp_set(flush, cpus);
+ }
+
+ /*
+ * We can flush not more than max_gvas with one hypercall. Flush the
+ * whole address space if we were asked to do more.
+ */
+ max_gvas = (PAGE_SIZE - sizeof(*flush) - nr_bank*8) / 8;
+
+ if (end == TLB_FLUSH_ALL ||
+ (end && ((end - start)/(PAGE_SIZE*PAGE_SIZE)) > max_gvas)) {
+ if (end == TLB_FLUSH_ALL)
+ flush->flags |= HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY;
+
+ status = hv_do_rep_hypercall(
+ HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX,
+ 0, nr_bank + 2, flush, NULL);
+ } else {
+ cur = start;
+ gva_n = nr_bank;
+ do {
+ flush->gva_list[gva_n] = cur & PAGE_MASK;
+ /*
+ * Lower 12 bits encode the number of additional
+ * pages to flush (in addition to the 'cur' page).
+ */
+ if (end >= cur + PAGE_SIZE * PAGE_SIZE)
+ flush->gva_list[gva_n] |= ~PAGE_MASK;
+ else if (end > cur)
+ flush->gva_list[gva_n] |=
+ (end - cur - 1) >> PAGE_SHIFT;
+
+ cur += PAGE_SIZE * PAGE_SIZE;
+ ++gva_n;
+
+ } while (cur < end);
+
+ status = hv_do_rep_hypercall(
+ HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX,
+ gva_n, nr_bank + 2, flush, NULL);
+ }
+
+ local_irq_restore(flags);
+
+ if (!(status & 0xffff))
+ return;
+do_native:
+ native_flush_tlb_others(cpus, mm, start, end);
+}
+
void hyperv_setup_mmu_ops(void)
{
- if (ms_hyperv.hints & HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED) {
+ if (!(ms_hyperv.hints & HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED))
+ return;
+
+ if (!(ms_hyperv.hints & HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED)) {
pr_info("Hyper-V: Using hypercall for remote TLB flush\n");
pv_mmu_ops.flush_tlb_others = hyperv_flush_tlb_others;
+ } else {
+ pr_info("Hyper-V: Using ext hypercall for remote TLB flush\n");
+ pv_mmu_ops.flush_tlb_others = hyperv_flush_tlb_others_ex;
}
}

void hyper_alloc_mmu(void)
{
- if (ms_hyperv.hints & HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED)
+ if (!(ms_hyperv.hints & HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED))
+ return;
+
+ if (!(ms_hyperv.hints & HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
pcpu_flush = __alloc_percpu(PAGE_SIZE, PAGE_SIZE);
+ else
+ pcpu_flush_ex = __alloc_percpu(PAGE_SIZE, PAGE_SIZE);
}
diff --git a/arch/x86/include/uapi/asm/hyperv.h b/arch/x86/include/uapi/asm/hyperv.h
index 3d44036..c697e20 100644
--- a/arch/x86/include/uapi/asm/hyperv.h
+++ b/arch/x86/include/uapi/asm/hyperv.h
@@ -152,6 +152,9 @@
*/
#define HV_X64_DEPRECATING_AEOI_RECOMMENDED (1 << 9)

+/* Recommend using the newer ExProcessorMasks interface */
+#define HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED (1 << 11)
+
/*
* Crash notification flag.
*/
@@ -242,6 +245,8 @@
#define HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE 0x0002
#define HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST 0x0003
#define HVCALL_NOTIFY_LONG_SPIN_WAIT 0x0008
+#define HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX 0x0013
+#define HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX 0x0014
#define HVCALL_POST_MESSAGE 0x005c
#define HVCALL_SIGNAL_EVENT 0x005d

@@ -263,6 +268,11 @@
#define HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY 0x00000004
#define HV_FLUSH_USE_EXTENDED_RANGE_FORMAT 0x00000008

+enum HV_GENERIC_SET_FORMAT {
+ HV_GENERIC_SET_SPARCE_4K,
+ HV_GENERIC_SET_ALL,
+};
+
/* Hypercall interface */
union hv_hypercall_input {
u64 as_uint64;
--
2.9.4