4.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
commit 110d2a7fc39725d2c29d2fede4f34a35a4f98882 upstream.
Commit 1268ed0c474a ("x86/hyper-v: Fix the circular dependency in IPI
enlightenment") pre-filled hv_vp_index with VP_INVAL so it is now
(theoretically) possible to observe hv_cpu_number_to_vp_number()
returning VP_INVAL. We need to check for that in hyperv_flush_tlb_others().
Not checking for VP_INVAL on the first call site where we do
if (hv_cpu_number_to_vp_number(cpumask_last(cpus)) >= 64)
goto do_ex_hypercall;
is OK, in case we're eligible for non-ex hypercall we'll catch the
issue later in for_each_cpu() cycle and in case we'll be doing ex-
hypercall cpumask_to_vpset() will fail.
It would be nice to change hv_cpu_number_to_vp_number() return
value's type to 'u32' but this will likely be a bigger change as
all call sites need to be checked first.
Fixes: 1268ed0c474a ("x86/hyper-v: Fix the circular dependency in IPI enlightenment")
Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
Cc: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx>
Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
Cc: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>
Cc: "Michael Kelley (EOSG)" <Michael.H.Kelley@xxxxxxxxxxxxx>
Cc: devel@xxxxxxxxxxxxxxxxxxxxxx
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Link: https://lkml.kernel.org/r/20180709174012.17429-3-vkuznets@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/hyperv/mmu.c | 5 +++++
1 file changed, 5 insertions(+)
--- a/arch/x86/hyperv/mmu.c
+++ b/arch/x86/hyperv/mmu.c
@@ -95,6 +95,11 @@ static void hyperv_flush_tlb_others(cons
} else {
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_native;
