From: Borislav Petkov <bp@alien8.de>
To: Sean Christopherson <seanjc@google.com>
Cc: Andy Lutomirski <luto@amacapital.net>,
Masami Hiramatsu <mhiramat@kernel.org>, X86 ML <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v1 04/19] x86/insn-eval: Handle return values from the decoder
Date: Mon, 28 Dec 2020 20:06:15 +0100 [thread overview]
Message-ID: <20201228190615.GC20321@zn.tnic> (raw)
In-Reply-To: <X+opI92rzCNZ151F@google.com>
On Mon, Dec 28, 2020 at 10:51:15AM -0800, Sean Christopherson wrote:
> This patch is incomplete/inconsistent, and arguably wrong.
>
> - get_eff_addr_reg() and get_eff_addr_modrm() still ignore the return of
> insn_get_modrm() after this patch.
Ah, will fix, thx.
> - Calling insn_get_modrm() from get_eff_addr_sib() is unnecessary (unless the
> caller passed uninitialized garbage in @insn) as get_eff_addr_sib() is
> called if and only if sib.nbytes!=0, and sib.nbytes can be non-zero if and
> only if the modrm and sib have been got.
>
> - get_addr_ref_16() does insn_get_displacement, i.e. guarantees the modrm is
> parsed, while the 32/64 variants do not.
>
> What about adding a prereq patch (or three) to call insn_get_displacement() in
> insn_get_addr_ref() prior to switching on insn->addr_bytes? Then the various
> internal helpers could be changed to either omit the sanity checks entirely or
> WARN on invalid calls? Or better yet, add an INSN_WARN_ON() macro that compiles
> out the checks by default? E.g. something like:
So the idea is one construction site at a time (that's a German saying :)).
This set deals with whacking the insn decoder into returning
proper error/success values. The next set should do
simplifications/fixes/cleanups/whatever but not all at the same time for
obvious reasons.
So yeah, I'm all for omitting useless code but let's do that ontop.
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2020-12-28 19:07 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-23 17:42 [PATCH v1 00/19] x86/insn: Add an insn_decode() API Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 01/19] x86/insn: Rename insn_decode() to insn_decode_regs() Borislav Petkov
2020-12-28 17:16 ` Sean Christopherson
2020-12-29 19:36 ` Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 02/19] x86/insn: Add @buf_len param to insn_init() kernel-doc comment Borislav Petkov
2020-12-28 1:44 ` Masami Hiramatsu
2020-12-23 17:42 ` [PATCH v1 03/19] x86/insn: Add an insn_decode() API Borislav Petkov
2020-12-28 1:15 ` Masami Hiramatsu
2020-12-29 20:06 ` Borislav Petkov
2020-12-30 9:00 ` Masami Hiramatsu
2020-12-30 9:28 ` Borislav Petkov
2021-01-06 5:21 ` Masami Hiramatsu
2021-01-08 18:59 ` Borislav Petkov
2021-01-12 11:34 ` Masami Hiramatsu
2021-01-13 18:06 ` Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 04/19] x86/insn-eval: Handle return values from the decoder Borislav Petkov
2020-12-28 18:51 ` Sean Christopherson
2020-12-28 19:06 ` Borislav Petkov [this message]
2020-12-23 17:42 ` [PATCH v1 05/19] x86/boot/compressed/sev-es: Convert to insn_decode() Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 06/19] perf/x86/intel/ds: Check insn_get_length() retval Borislav Petkov
2021-01-04 13:19 ` Peter Zijlstra
2021-01-19 10:40 ` Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 07/19] perf/x86/intel/ds: Check return values of insn decoder functions Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 08/19] x86/alternative: Use insn_decode() Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 09/19] x86/mce: Convert to insn_decode() Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 10/19] x86/kprobes: " Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 11/19] x86/sev-es: " Borislav Petkov
2020-12-25 10:50 ` kernel test robot
2020-12-25 12:33 ` Borislav Petkov
2020-12-28 19:15 ` Sean Christopherson
2021-01-21 16:58 ` Borislav Petkov
2021-01-21 22:35 ` Sean Christopherson
2020-12-23 17:42 ` [PATCH v1 12/19] x86/traps: " Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 13/19] x86/uprobes: " Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 14/19] x86/tools/insn_decoder_test: " Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 15/19] tools/objtool: " Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 16/19] x86/tools/insn_sanity: " Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 17/19] tools/perf: " Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 18/19] x86/insn: Remove kernel_insn_init() Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 19/19] x86/insn: Make insn_complete() static Borislav Petkov
2020-12-27 15:26 ` [PATCH v1 00/19] x86/insn: Add an insn_decode() API Tom Lendacky
2021-02-03 12:00 ` Borislav Petkov
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