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x86/hyperv: Check for required priviliges in hyperv_init()

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In hyperv_init() its presumed that it always has access to VP index and
hypercall MSRs while according to the specification it should be checked if
it's allowed to access the corresponding MSRs before accessing them.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: kvm@vger.kernel.org
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: "Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>
Cc: Roman Kagan <rkagan@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: devel@linuxdriverproject.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Cathy Avery <cavery@redhat.com>
Cc: Mohammed Gamal <mmorsy@redhat.com>
Link: https://lkml.kernel.org/r/20180124132337.30138-2-vkuznets@redhat.com
This commit is contained in:
Vitaly Kuznetsov 2018-01-24 14:23:31 +01:00 committed by Thomas Gleixner
parent 72906f3893
commit 89a8f6d490
1 changed files with 8 additions and 1 deletions
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9
arch/x86/hyperv/hv_init.c
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@ -110,12 +110,19 @@ static int hv_cpu_init(unsigned int cpu)
*/
void hyperv_init(void)
{
u64 guest_id;
u64 guest_id, required_msrs;
union hv_x64_msr_hypercall_contents hypercall_msr;
if (x86_hyper_type != X86_HYPER_MS_HYPERV)
return;
/* Absolutely required MSRs */
required_msrs = HV_X64_MSR_HYPERCALL_AVAILABLE |
HV_X64_MSR_VP_INDEX_AVAILABLE;
if ((ms_hyperv.features & required_msrs) != required_msrs)
return;
/* Allocate percpu VP index */
hv_vp_index = kmalloc_array(num_possible_cpus(), sizeof(*hv_vp_index),
GFP_KERNEL);