From: Borislav Petkov <bp@alien8.de>
To: Sean Christopherson <seanjc@google.com>
Cc: kernel test robot <lkp@intel.com>,
Andy Lutomirski <luto@amacapital.net>,
Masami Hiramatsu <mhiramat@kernel.org>,
kbuild-all@lists.01.org, clang-built-linux@googlegroups.com,
X86 ML <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v1 11/19] x86/sev-es: Convert to insn_decode()
Date: Thu, 21 Jan 2021 17:58:45 +0100 [thread overview]
Message-ID: <20210121165845.GD32060@zn.tnic> (raw)
In-Reply-To: <X+ouv0PN6dmva92i@google.com>
On Mon, Dec 28, 2020 at 11:15:11AM -0800, Sean Christopherson wrote:
> Alternatively, could the kernel case use insn_decode_regs()? If
> vc_fetch_insn_kernel() were also modified to mirror insn_fetch_from_user(), the
> two code paths could be unified except for the the fetch and the PFEC. E.g.
Personal Firearms Eligibility Check?
In any case, I prefer simple, easy to follow code at a quick glance.
Stuff like...
>
> static int vc_fetch_insn_kernel(struct es_em_ctxt *ctxt,
> unsigned char *buffer)
> {
> if (copy_from_kernel_nofault(buffer, (unsigned char *)ctxt->regs->ip, MAX_INSN_SIZE))
> return 0;
>
> return MAX_INSN_SIZE;
> }
>
> static enum es_result vc_decode_insn(struct es_em_ctxt *ctxt)
> {
> char buffer[MAX_INSN_SIZE];
> int nbytes;
>
> if (user_mode(ctxt->regs))
> nbytes = insn_fetch_from_user(ctxt->regs, buffer);
> else
> nbytes = vc_fetch_insn_kernel(ctxt, buffer);
>
> if (!nbytes) {
> ctxt->fi.vector = X86_TRAP_PF;
> ctxt->fi.error_code = X86_PF_INSTR;
> if (user_mode(ctxt->regs))
... this second repeated check here is not what I would call that.
But this is my personal preference only so it's up for a vote now.
:-)
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2021-01-21 17:00 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
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 [this message]
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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