Merge tag 'for-linus-5.0-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen fixes from Juergen Gross:

 - Several fixes for the Xen pvcalls drivers (1 fix for the backend and
   8 for the frontend).

 - A fix for a rather longstanding bug in the Xen sched_clock()
   interface which led to weird time jumps when migrating the system.

 - A fix for avoiding accesses to x2apic MSRs in Xen PV guests.

* tag 'for-linus-5.0-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen: Fix x86 sched_clock() interface for xen
  pvcalls-front: fix potential null dereference
  always clear the X2APIC_ENABLE bit for PV guest
  pvcalls-front: Avoid get_free_pages(GFP_KERNEL) under spinlock
  xen/pvcalls: remove set but not used variable 'intf'
  pvcalls-back: set -ENOTCONN in pvcalls_conn_back_read
  pvcalls-front: don't return error when the ring is full
  pvcalls-front: properly allocate sk
  pvcalls-front: don't try to free unallocated rings
  pvcalls-front: read all data before closing the connection

2 files changed, 10 insertions, 7 deletions

diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 2f6787fc7106..c54a493e139a 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -898,10 +898,7 @@ static u64 xen_read_msr_safe(unsigned int msr, int *err)
 	val = native_read_msr_safe(msr, err);
 	switch (msr) {
 	case MSR_IA32_APICBASE:
-#ifdef CONFIG_X86_X2APIC
-		if (!(cpuid_ecx(1) & (1 << (X86_FEATURE_X2APIC & 31))))
-#endif
-			val &= ~X2APIC_ENABLE;
+		val &= ~X2APIC_ENABLE;
 		break;
 	}
 	return val;
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index 72bf446c3fee..6e29794573b7 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -361,8 +361,6 @@ void xen_timer_resume(void)
 {
 	int cpu;
 
-	pvclock_resume();
-
 	if (xen_clockevent != &xen_vcpuop_clockevent)
 		return;
 
@@ -379,12 +377,15 @@ static const struct pv_time_ops xen_time_ops __initconst = {
 };
 
 static struct pvclock_vsyscall_time_info *xen_clock __read_mostly;
+static u64 xen_clock_value_saved;
 
 void xen_save_time_memory_area(void)
 {
 	struct vcpu_register_time_memory_area t;
 	int ret;
 
+	xen_clock_value_saved = xen_clocksource_read() - xen_sched_clock_offset;
+
 	if (!xen_clock)
 		return;
 
@@ -404,7 +405,7 @@ void xen_restore_time_memory_area(void)
 	int ret;
 
 	if (!xen_clock)
-		return;
+		goto out;
 
 	t.addr.v = &xen_clock->pvti;
 
@@ -421,6 +422,11 @@ void xen_restore_time_memory_area(void)
 	if (ret != 0)
 		pr_notice("Cannot restore secondary vcpu_time_info (err %d)",
 			  ret);
+
+out:
+	/* Need pvclock_resume() before using xen_clocksource_read(). */
+	pvclock_resume();
+	xen_sched_clock_offset = xen_clocksource_read() - xen_clock_value_saved;
 }
 
 static void xen_setup_vsyscall_time_info(void)