x86/hyperv: Fix hypercalls with extended CPU ranges for TLB flushing

Do not consider the fixed size of hv_vp_set when passing the variable
header size to hv_do_rep_hypercall().

The Hyper-V hypervisor specification states that for a hypercall with a
variable header only the size of the variable portion should be supplied
via the input control.

For HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX/LIST_EX calls that means the
fixed portion of hv_vp_set should not be considered.

That fixes random failures of some applications that are unexpectedly
killed with SIGBUS or SIGSEGV.

Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jork Loeser <Jork.Loeser@microsoft.com>
Cc: Josh Poulson <jopoulso@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Simon Xiao <sixiao@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: devel@linuxdriverproject.org
Fixes: 628f54cc6451 ("x86/hyper-v: Support extended CPU ranges for TLB flush hypercalls")
Link: http://lkml.kernel.org/r/1507210469-29065-1-git-send-email-marcelo.cerri@canonical.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/arch/x86/hyperv/mmu.c b/arch/x86/hyperv/mmu.c
index f21cebbb5f6c..9cc9e1c1e2db 100644
--- a/arch/x86/hyperv/mmu.c
+++ b/arch/x86/hyperv/mmu.c
@@ -251,18 +251,18 @@ static void hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
                 flush->flags |= HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY;
                 status = hv_do_rep_hypercall(
                         HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX,
-                        0, nr_bank + 2, flush, NULL);
+                        0, nr_bank, flush, NULL);
         } else if (info->end &&
                    ((info->end - info->start)/HV_TLB_FLUSH_UNIT) > max_gvas) {
                 status = hv_do_rep_hypercall(
                         HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX,
-                        0, nr_bank + 2, flush, NULL);
+                        0, nr_bank, flush, NULL);
         } else {
                 gva_n = fill_gva_list(flush->gva_list, nr_bank,
                                       info->start, info->end);
                 status = hv_do_rep_hypercall(
                         HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX,
-                        gva_n, nr_bank + 2, flush, NULL);
+                        gva_n, nr_bank, flush, NULL);
         }
 
         local_irq_restore(flags);