x86/hyper-v: Add HvFlushGuestAddressList hypercall support

Hyper-V provides HvFlushGuestAddressList() hypercall to flush EPT tlb
with specified ranges. This patch is to add the hypercall support.

Reviewed-by:  Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 80 insertions, 0 deletions

diff --git a/arch/x86/hyperv/nested.c b/arch/x86/hyperv/nested.c
index b8e60cc50461..dd0a843f766d 100644
--- a/arch/x86/hyperv/nested.c
+++ b/arch/x86/hyperv/nested.c
@@ -7,6 +7,7 @@
  *
  * Author : Lan Tianyu <Tianyu.Lan@microsoft.com>
  */
+#define pr_fmt(fmt)  "Hyper-V: " fmt
 
 
 #include <linux/types.h>
@@ -54,3 +55,82 @@ fault:
 	return ret;
 }
 EXPORT_SYMBOL_GPL(hyperv_flush_guest_mapping);
+
+int hyperv_fill_flush_guest_mapping_list(
+		struct hv_guest_mapping_flush_list *flush,
+		u64 start_gfn, u64 pages)
+{
+	u64 cur = start_gfn;
+	u64 additional_pages;
+	int gpa_n = 0;
+
+	do {
+		/*
+		 * If flush requests exceed max flush count, go back to
+		 * flush tlbs without range.
+		 */
+		if (gpa_n >= HV_MAX_FLUSH_REP_COUNT)
+			return -ENOSPC;
+
+		additional_pages = min_t(u64, pages, HV_MAX_FLUSH_PAGES) - 1;
+
+		flush->gpa_list[gpa_n].page.additional_pages = additional_pages;
+		flush->gpa_list[gpa_n].page.largepage = false;
+		flush->gpa_list[gpa_n].page.basepfn = cur;
+
+		pages -= additional_pages + 1;
+		cur += additional_pages + 1;
+		gpa_n++;
+	} while (pages > 0);
+
+	return gpa_n;
+}
+EXPORT_SYMBOL_GPL(hyperv_fill_flush_guest_mapping_list);
+
+int hyperv_flush_guest_mapping_range(u64 as,
+		hyperv_fill_flush_list_func fill_flush_list_func, void *data)
+{
+	struct hv_guest_mapping_flush_list **flush_pcpu;
+	struct hv_guest_mapping_flush_list *flush;
+	u64 status = 0;
+	unsigned long flags;
+	int ret = -ENOTSUPP;
+	int gpa_n = 0;
+
+	if (!hv_hypercall_pg || !fill_flush_list_func)
+		goto fault;
+
+	local_irq_save(flags);
+
+	flush_pcpu = (struct hv_guest_mapping_flush_list **)
+		this_cpu_ptr(hyperv_pcpu_input_arg);
+
+	flush = *flush_pcpu;
+	if (unlikely(!flush)) {
+		local_irq_restore(flags);
+		goto fault;
+	}
+
+	flush->address_space = as;
+	flush->flags = 0;
+
+	gpa_n = fill_flush_list_func(flush, data);
+	if (gpa_n < 0) {
+		local_irq_restore(flags);
+		goto fault;
+	}
+
+	status = hv_do_rep_hypercall(HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_LIST,
+				     gpa_n, 0, flush, NULL);
+
+	local_irq_restore(flags);
+
+	if (!(status & HV_HYPERCALL_RESULT_MASK))
+		ret = 0;
+	else
+		ret = status;
+fault:
+	trace_hyperv_nested_flush_guest_mapping_range(as, ret);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(hyperv_flush_guest_mapping_range);