Commit-ID: 89a8f6d4904c8cf3ff8fee9fdaff392a6bbb8bf6 Gitweb: https://git.kernel.org/tip/89a8f6d4904c8cf3ff8fee9fdaff392a6bbb8bf6 Author: Vitaly Kuznetsov <[email protected]> AuthorDate: Wed, 24 Jan 2018 14:23:31 +0100 Committer: Thomas Gleixner <[email protected]> CommitDate: Tue, 30 Jan 2018 23:55:32 +0100
x86/hyperv: Check for required priviliges in hyperv_init() 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 <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Thomas Gleixner <[email protected]> Cc: Stephen Hemminger <[email protected]> Cc: [email protected] Cc: Radim Krčmář <[email protected]> Cc: Haiyang Zhang <[email protected]> Cc: "Michael Kelley (EOSG)" <[email protected]> Cc: Roman Kagan <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: [email protected] Cc: Paolo Bonzini <[email protected]> Cc: "K. Y. Srinivasan" <[email protected]> Cc: Cathy Avery <[email protected]> Cc: Mohammed Gamal <[email protected]> Link: https://lkml.kernel.org/r/[email protected] --- arch/x86/hyperv/hv_init.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index 189a398..21f9d53 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -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);
