From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Alexandru Isaila <aisaila@bitdefender.com>, xen-devel@lists.xen.org
Cc: boris.ostrovsky@oracle.com, tamas@tklengyel.com,
jbeulich@suse.com, suravee.suthikulpanit@amd.com,
rcojocaru@bitdefender.com
Subject: Re: [PATCH v3 2/4] hvm/svm: Enable Breakpoint events
Date: Mon, 12 Feb 2018 15:54:47 +0000 [thread overview]
Message-ID: <5aba8de5-4cca-9a4b-0f82-ec032eb48b96@citrix.com> (raw)
In-Reply-To: <1518448098-6493-3-git-send-email-aisaila@bitdefender.com>
On 12/02/18 15:08, Alexandru Isaila wrote:
> @@ -2619,14 +2634,31 @@ void svm_vmexit_handler(struct cpu_user_regs *regs)
> break;
>
> case VMEXIT_EXCEPTION_BP:
> - if ( !v->domain->debugger_attached )
> - goto unexpected_exit_type;
> - /* AMD Vol2, 15.11: INT3, INTO, BOUND intercepts do not update RIP. */
> - if ( (inst_len = __get_instruction_length(v, INSTR_INT3)) == 0 )
> + inst_len = __get_instruction_length(v, INSTR_INT3);
There are multiple ways of ending up with this vmexit, and INT3 is not
the only way.
The old code was somewhat broken (but only in the case that a debugger
was attached), but now with this introspection hook active, executing
`0xcd 0x03` will end up crashing the domain because of a length mismatch
looking for 0xcc.
You need to inspect EXITINTINFO to work out what went on here, and
distinguish INT3 from INT $3.
Can I suggest that you run this unit test
http://xenbits.xen.org/docs/xtf/test-swint-emulation.html under debug
introspection an check that you get all expected events? Every time we
touch this code, we seem to break it :(
~Andrew
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next prev parent reply other threads:[~2018-02-12 15:54 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-12 15:08 [PATCH v3 0/4] hvm/svm: Enable vm events for SVM Alexandru Isaila
2018-02-12 15:08 ` [PATCH v3 1/4] asm-x86/monitor: Fix monitor capability reporting on SVM systems Alexandru Isaila
2018-02-12 15:13 ` Andrew Cooper
2018-02-14 17:47 ` Andrew Cooper
2018-02-14 17:56 ` Razvan Cojocaru
2018-02-14 21:34 ` Tamas K Lengyel
2018-02-12 15:08 ` [PATCH v3 2/4] hvm/svm: Enable Breakpoint events Alexandru Isaila
2018-02-12 15:49 ` Tamas K Lengyel
2018-02-12 15:54 ` Andrew Cooper [this message]
2018-02-12 16:03 ` Tamas K Lengyel
2018-02-13 12:48 ` Alexandru Stefan ISAILA
2018-02-14 16:10 ` Alexandru Stefan ISAILA
2018-02-14 18:22 ` Andrew Cooper
2018-02-14 19:11 ` Andrew Cooper
2018-02-15 8:20 ` Alexandru Stefan ISAILA
2018-02-12 15:08 ` [PATCH v3 3/4] hvm/svm: Enable MSR events Alexandru Isaila
2018-02-12 15:08 ` [PATCH v3 4/4] hvm/svm: Enable CR events Alexandru Isaila
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