[RFC 12/16] x86/kvm: Share steal time page with host

[Kirill A. Shutemov]

struct kvm_steal_time is shared between guest and host. Mark it as
shared.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
 arch/x86/kernel/kvm.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index f50d65df4412..b0f445796ed1 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -286,11 +286,15 @@ static void kvm_register_steal_time(void)
 {
 	int cpu = smp_processor_id();
 	struct kvm_steal_time *st = &per_cpu(steal_time, cpu);
+	unsigned long phys;
 
 	if (!has_steal_clock)
 		return;
 
-	wrmsrl(MSR_KVM_STEAL_TIME, (slow_virt_to_phys(st) | KVM_MSR_ENABLED));
+	phys = slow_virt_to_phys(st);
+	if (kvm_mem_protected())
+		kvm_hypercall2(KVM_HC_MEM_SHARE, phys >> PAGE_SHIFT, 1);
+	wrmsrl(MSR_KVM_STEAL_TIME, (phys | KVM_MSR_ENABLED));
 	pr_info("kvm-stealtime: cpu %d, msr %llx\n",
 		cpu, (unsigned long long) slow_virt_to_phys(st));
 }
-- 
2.26.2