Merge tag 'for-linus-4.18-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen fixes from Juergen Gross:
 "This contains the following fixes/cleanups:

   - the removal of a BUG_ON() which wasn't necessary and which could
     trigger now due to a recent change

   - a correction of a long standing bug happening very rarely in Xen
     dom0 when a hypercall buffer from user land was not accessible by
     the hypervisor for very short periods of time due to e.g. page
     migration or compaction

   - usage of EXPORT_SYMBOL_GPL() instead of EXPORT_SYMBOL() in a
     Xen-related driver (no breakage possible as using those symbols
     without others already exported via EXPORT-SYMBOL_GPL() wouldn't
     make any sense)

   - a simplification for Xen PVH or Xen ARM guests

   - some additional error handling for callers of xenbus_printf()"

* tag 'for-linus-4.18-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen: Remove unnecessary BUG_ON from __unbind_from_irq()
  xen: add new hypercall buffer mapping device
  xen/scsiback: add error handling for xenbus_printf
  scsi: xen-scsifront: add error handling for xenbus_printf
  xen/grant-table: Export gnttab_{alloc|free}_pages as GPL
  xen: add error handling for xenbus_printf
  xen: share start flags between PV and PVH

4 files changed, 13 insertions, 3 deletions

diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 8073625371f5..07060e5b5864 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -59,6 +59,9 @@ struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata;
 
 static __read_mostly unsigned int xen_events_irq;
 
+uint32_t xen_start_flags;
+EXPORT_SYMBOL(xen_start_flags);
+
 int xen_remap_domain_gfn_array(struct vm_area_struct *vma,
 			       unsigned long addr,
 			       xen_pfn_t *gfn, int nr,
@@ -293,9 +296,7 @@ void __init xen_early_init(void)
 	xen_setup_features();
 
 	if (xen_feature(XENFEAT_dom0))
-		xen_start_info->flags |= SIF_INITDOMAIN|SIF_PRIVILEGED;
-	else
-		xen_start_info->flags &= ~(SIF_INITDOMAIN|SIF_PRIVILEGED);
+		xen_start_flags |= SIF_INITDOMAIN|SIF_PRIVILEGED;
 
 	if (!console_set_on_cmdline && !xen_initial_domain())
 		add_preferred_console("hvc", 0, NULL);
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index c9081c6671f0..3b5318505c69 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -65,6 +65,13 @@ __read_mostly int xen_have_vector_callback;
 EXPORT_SYMBOL_GPL(xen_have_vector_callback);
 
 /*
+ * NB: needs to live in .data because it's used by xen_prepare_pvh which runs
+ * before clearing the bss.
+ */
+uint32_t xen_start_flags __attribute__((section(".data"))) = 0;
+EXPORT_SYMBOL(xen_start_flags);
+
+/*
  * Point at some empty memory to start with. We map the real shared_info
  * page as soon as fixmap is up and running.
  */
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 357969a3697c..8d4e2e1ae60b 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -1203,6 +1203,7 @@ asmlinkage __visible void __init xen_start_kernel(void)
 		return;
 
 	xen_domain_type = XEN_PV_DOMAIN;
+	xen_start_flags = xen_start_info->flags;
 
 	xen_setup_features();
 
diff --git a/arch/x86/xen/enlighten_pvh.c b/arch/x86/xen/enlighten_pvh.c
index aa1c6a6831a9..c85d1a88f476 100644
--- a/arch/x86/xen/enlighten_pvh.c
+++ b/arch/x86/xen/enlighten_pvh.c
@@ -97,6 +97,7 @@ void __init xen_prepare_pvh(void)
 	}
 
 	xen_pvh = 1;
+	xen_start_flags = pvh_start_info.flags;
 
 	msr = cpuid_ebx(xen_cpuid_base() + 2);
 	pfn = __pa(hypercall_page);