On 01/02/2019 14:52, Tamas K Lengyel wrote:
> On Fri, Feb 1, 2019 at 7:49 AM Andrew Cooper <andrew.coop...@citrix.com>
> wrote:
>> c/s 9338a37d "x86/svm: implement debug events" added support for
>> introspecting
>> ICEBP debug exceptions, but didn't account for the fact that
>> svm_get_insn_len() (previously __get_instruction_length) can fail and may
>> already raise #GP for the guest.
>>
>> If svm_get_insn_len() fails, return back to guest context rather than
>> continuing and mistaking a trap-style VMExit for a fault-style one.
>>
>> Spotted by Coverity.
>>
>> Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
>> ---
>> CC: Jan Beulich <jbeul...@suse.com>
>> CC: Wei Liu <wei.l...@citrix.com>
>> CC: Roger Pau Monné <roger....@citrix.com>
>> CC: Boris Ostrovsky <boris.ostrov...@oracle.com>
>> CC: Suravee Suthikulpanit <suravee.suthikulpa...@amd.com>
>> CC: Brian Woods <brian.wo...@amd.com>
>> CC: Juergen Gross <jgr...@suse.com>
>> CC: Razvan Cojocaru <rcojoc...@bitdefender.com>
>> CC: Tamas K Lengyel <ta...@tklengyel.com>
>>
>> This wants backporting to Xen 4.11
>> ---
>> xen/arch/x86/hvm/svm/svm.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
>> index 2584b90..e21091c 100644
>> --- a/xen/arch/x86/hvm/svm/svm.c
>> +++ b/xen/arch/x86/hvm/svm/svm.c
>> @@ -2758,6 +2758,9 @@ void svm_vmexit_handler(struct cpu_user_regs *regs)
>> {
>> trap_type = X86_EVENTTYPE_PRI_SW_EXCEPTION;
>> inst_len = svm_get_insn_len(v, INSTR_ICEBP);
>> +
>> + if ( !instr_len )
> Should that have been inst_len instead of instr_len?
Bah - serves me right not to refresh my patch before sending it. Yes -
this is a typo.
~Andrew
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel
