Commit 110d2a7f authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by Thomas Gleixner
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x86/hyper-v: Check for VP_INVAL in hyperv_flush_tlb_others()

Commit 1268ed0c ("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: 1268ed0c

 ("x86/hyper-v: Fix the circular dependency in IPI enlightenment")
Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: "Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>
Cc: devel@linuxdriverproject.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lkml.kernel.org/r/20180709174012.17429-3-vkuznets@redhat.com
parent 0f0caa52
...@@ -111,6 +111,11 @@ static void hyperv_flush_tlb_others(const struct cpumask *cpus, ...@@ -111,6 +111,11 @@ static void hyperv_flush_tlb_others(const struct cpumask *cpus,
for_each_cpu(cpu, cpus) { for_each_cpu(cpu, cpus) {
vcpu = hv_cpu_number_to_vp_number(cpu); vcpu = hv_cpu_number_to_vp_number(cpu);
if (vcpu == VP_INVAL) {
local_irq_restore(flags);
goto do_native;
}
if (vcpu >= 64) if (vcpu >= 64)
goto do_ex_hypercall; goto do_ex_hypercall;
......
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