linux-kernel - [tip:x86/urgent] x86/hyperv: Fix hypercalls with extended CPU ranges for TLB flushing

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Date:   Tue, 10 Oct 2017 07:58:10 -0700
From:   tip-bot for Marcelo Henrique Cerri <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     kys@...rosoft.com, vkuznets@...hat.com,
        torvalds@...ux-foundation.org, Jork.Loeser@...rosoft.com,
        jopoulso@...rosoft.com, sixiao@...rosoft.com, hpa@...or.com,
        linux-kernel@...r.kernel.org, decui@...rosoft.com,
        peterz@...radead.org, haiyangz@...rosoft.com,
        sthemmin@...rosoft.com, marcelo.cerri@...onical.com,
        mingo@...nel.org, tglx@...utronix.de
Subject: [tip:x86/urgent] x86/hyperv: Fix hypercalls with extended CPU
 ranges for TLB flushing

Commit-ID:  ab7ff471aa5db670197070760f022622793da7e5
Gitweb:     https://git.kernel.org/tip/ab7ff471aa5db670197070760f022622793da7e5
Author:     Marcelo Henrique Cerri <marcelo.cerri@...onical.com>
AuthorDate: Thu, 5 Oct 2017 10:34:29 -0300
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Tue, 10 Oct 2017 12:54:56 +0200

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@...onical.com>
Cc: Dexuan Cui <decui@...rosoft.com>
Cc: Haiyang Zhang <haiyangz@...rosoft.com>
Cc: Jork Loeser <Jork.Loeser@...rosoft.com>
Cc: Josh Poulson <jopoulso@...rosoft.com>
Cc: K. Y. Srinivasan <kys@...rosoft.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Simon Xiao <sixiao@...rosoft.com>
Cc: Stephen Hemminger <sthemmin@...rosoft.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Vitaly Kuznetsov <vkuznets@...hat.com>
Cc: devel@...uxdriverproject.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@...nel.org>
---
 arch/x86/hyperv/mmu.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/hyperv/mmu.c b/arch/x86/hyperv/mmu.c
index f21cebb..9cc9e1c 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);