1 files changed, 244 insertions, 0 deletions
diff --git a/arch/x86/hyperv/mmu.c b/arch/x86/hyperv/mmu.c
new file mode 100644
index 000000000..e666f7eaf
--- /dev/null
+++ b/arch/x86/hyperv/mmu.c
@@ -0,0 +1,244 @@
+#define pr_fmt(fmt)  "Hyper-V: " fmt
+
+#include <linux/hyperv.h>
+#include <linux/log2.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include <asm/fpu/api.h>
+#include <asm/mshyperv.h>
+#include <asm/msr.h>
+#include <asm/tlbflush.h>
+#include <asm/tlb.h>
+
+#define CREATE_TRACE_POINTS
+#include <asm/trace/hyperv.h>
+
+/* Each gva in gva_list encodes up to 4096 pages to flush */
+#define HV_TLB_FLUSH_UNIT (4096 * PAGE_SIZE)
+
+static u64 hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
+				      const struct flush_tlb_info *info);
+
+/*
+ * Fills in gva_list starting from offset. Returns the number of items added.
+ */
+static inline int fill_gva_list(u64 gva_list[], int offset,
+				unsigned long start, unsigned long end)
+{
+	int gva_n = offset;
+	unsigned long cur = start, diff;
+
+	do {
+		diff = end > cur ? end - cur : 0;
+
+		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 (diff >= HV_TLB_FLUSH_UNIT) {
+			gva_list[gva_n] |= ~PAGE_MASK;
+			cur += HV_TLB_FLUSH_UNIT;
+		}  else if (diff) {
+			gva_list[gva_n] |= (diff - 1) >> PAGE_SHIFT;
+			cur = end;
+		}
+
+		gva_n++;
+
+	} while (cur < end);
+
+	return gva_n - offset;
+}
+
+static void hyperv_flush_tlb_others(const struct cpumask *cpus,
+				    const struct flush_tlb_info *info)
+{
+	int cpu, vcpu, gva_n, max_gvas;
+	struct hv_tlb_flush **flush_pcpu;
+	struct hv_tlb_flush *flush;
+	u64 status = U64_MAX;
+	unsigned long flags;
+
+	trace_hyperv_mmu_flush_tlb_others(cpus, info);
+
+	if (!hv_hypercall_pg)
+		goto do_native;
+
+	local_irq_save(flags);
+
+	/*
+	 * Only check the mask _after_ interrupt has been disabled to avoid the
+	 * mask changing under our feet.
+	 */
+	if (cpumask_empty(cpus)) {
+		local_irq_restore(flags);
+		return;
+	}
+
+	flush_pcpu = (struct hv_tlb_flush **)
+		     this_cpu_ptr(hyperv_pcpu_input_arg);
+
+	flush = *flush_pcpu;
+
+	if (unlikely(!flush)) {
+		local_irq_restore(flags);
+		goto do_native;
+	}
+
+	if (info->mm) {
+		/*
+		 * AddressSpace argument must match the CR3 with PCID bits
+		 * stripped out.
+		 */
+		flush->address_space = virt_to_phys(info->mm->pgd);
+		flush->address_space &= CR3_ADDR_MASK;
+		flush->flags = 0;
+	} else {
+		flush->address_space = 0;
+		flush->flags = HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES;
+	}
+
+	flush->processor_mask = 0;
+	if (cpumask_equal(cpus, cpu_present_mask)) {
+		flush->flags |= HV_FLUSH_ALL_PROCESSORS;
+	} else {
+		/*
+		 * From the supplied CPU set we need to figure out if we can get
+		 * away with cheaper HVCALL_FLUSH_VIRTUAL_ADDRESS_{LIST,SPACE}
+		 * hypercalls. This is possible when the highest VP number in
+		 * the set is < 64. As VP numbers are usually in ascending order
+		 * and match Linux CPU ids, here is an optimization: we check
+		 * the VP number for the highest bit in the supplied set first
+		 * so we can quickly find out if using *_EX hypercalls is a
+		 * must. We will also check all VP numbers when walking the
+		 * supplied CPU set to remain correct in all cases.
+		 */
+		if (hv_cpu_number_to_vp_number(cpumask_last(cpus)) >= 64)
+			goto do_ex_hypercall;
+
+		for_each_cpu(cpu, cpus) {
+			vcpu = hv_cpu_number_to_vp_number(cpu);
+			if (vcpu == VP_INVAL) {
+				local_irq_restore(flags);
+				goto do_native;
+			}
+
+			if (vcpu >= 64)
+				goto do_ex_hypercall;
+
+			__set_bit(vcpu, (unsigned long *)
+				  &flush->processor_mask);
+		}
+	}
+
+	/*
+	 * 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)) / sizeof(flush->gva_list[0]);
+
+	if (info->end == TLB_FLUSH_ALL) {
+		flush->flags |= HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY;
+		status = hv_do_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE,
+					 flush, NULL);
+	} else if (info->end &&
+		   ((info->end - info->start)/HV_TLB_FLUSH_UNIT) > max_gvas) {
+		status = hv_do_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE,
+					 flush, NULL);
+	} else {
+		gva_n = fill_gva_list(flush->gva_list, 0,
+				      info->start, info->end);
+		status = hv_do_rep_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST,
+					     gva_n, 0, flush, NULL);
+	}
+	goto check_status;
+
+do_ex_hypercall:
+	status = hyperv_flush_tlb_others_ex(cpus, info);
+
+check_status:
+	local_irq_restore(flags);
+
+	if (!(status & HV_HYPERCALL_RESULT_MASK))
+		return;
+do_native:
+	native_flush_tlb_others(cpus, info);
+}
+
+static u64 hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
+				      const struct flush_tlb_info *info)
+{
+	int nr_bank = 0, max_gvas, gva_n;
+	struct hv_tlb_flush_ex **flush_pcpu;
+	struct hv_tlb_flush_ex *flush;
+	u64 status;
+
+	if (!(ms_hyperv.hints & HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
+		return U64_MAX;
+
+	flush_pcpu = (struct hv_tlb_flush_ex **)
+		     this_cpu_ptr(hyperv_pcpu_input_arg);
+
+	flush = *flush_pcpu;
+
+	if (info->mm) {
+		/*
+		 * AddressSpace argument must match the CR3 with PCID bits
+		 * stripped out.
+		 */
+		flush->address_space = virt_to_phys(info->mm->pgd);
+		flush->address_space &= CR3_ADDR_MASK;
+		flush->flags = 0;
+	} else {
+		flush->address_space = 0;
+		flush->flags = HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES;
+	}
+
+	flush->hv_vp_set.valid_bank_mask = 0;
+
+	flush->hv_vp_set.format = HV_GENERIC_SET_SPARSE_4K;
+	nr_bank = cpumask_to_vpset(&(flush->hv_vp_set), cpus);
+	if (nr_bank < 0)
+		return U64_MAX;
+
+	/*
+	 * 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 *
+		 sizeof(flush->hv_vp_set.bank_contents[0])) /
+		sizeof(flush->gva_list[0]);
+
+	if (info->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, flush, NULL);
+	} else if (info->end &&
+		   ((info->end - info->start)/HV_TLB_FLUSH_UNIT) > max_gvas) {
+		status = hv_do_rep_hypercall(
+			HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX,
+			0, nr_bank, flush, NULL);
+	} else {
+		gva_n = fill_gva_list(flush->gva_list, nr_bank,
+				      info->start, info->end);
+		status = hv_do_rep_hypercall(
+			HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX,
+			gva_n, nr_bank, flush, NULL);
+	}
+
+	return status;
+}
+
+void hyperv_setup_mmu_ops(void)
+{
+	if (!(ms_hyperv.hints & HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED))
+		return;
+
+	pr_info("Using hypercall for remote TLB flush\n");
+	pv_mmu_ops.flush_tlb_others = hyperv_flush_tlb_others;
+	pv_mmu_ops.tlb_remove_table = tlb_remove_table;
+}