From: Dave Hansen <dave.hansen@intel.com>
To: Wu Zongyong <wuzongyong@linux.alibaba.com>,
tglx@linutronix.de, mingo@redhat.com,
dave.hansen@linux.intel.com, x86@kernel.org,
linux-kernel@vger.kernel.org
Cc: thomas.lendacky@amd.com, tony.luck@intel.com,
kirill.shutemov@linux.intel.com, wutu.xq2@linux.alibaba.com
Subject: Re: [RFC PATCH] x86/insn: support decode MOVSXD instruction for MMIO
Date: Fri, 31 Mar 2023 08:30:22 -0700 [thread overview]
Message-ID: <13f83347-e618-b976-78cc-88f991dc80f2@intel.com> (raw)
In-Reply-To: <1655f5dc49ab77f94e350ecbdc93e8d9b31acf61.1680058548.git.wuzongyong@linux.alibaba.com>
On 3/28/23 19:59, Wu Zongyong wrote:
> It seems MOVSXD which opcode is 0x63 is not handled, support
> to decode it in insn_decode_mmio().
...
> switch (insn->opcode.bytes[0]) {
> + case 0x63: /* MOVSXD r64, m32 */
> + *bytes = 4;
> + type = INSN_MMIO_READ_SIGN_EXTEND;
> + break;
The kernel does not support _arbitrary_ memory access instructions
messing with MMIO.
Before even considering this, I'd want to see a very concrete
explanation for why _this_ instruction in particular is required. I'd
also want to make sure this doesn't set us off down a slippery slope
trying to make the MMIO decoder more expansive.
prev parent reply other threads:[~2023-03-31 15:30 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-29 2:59 [RFC PATCH] x86/insn: support decode MOVSXD instruction for MMIO Wu Zongyong
2023-03-29 13:49 ` Tom Lendacky
2023-03-30 2:55 ` Wu Zongyong
2023-03-30 12:39 ` kirill.shutemov
2023-03-31 2:24 ` Wu Zongyong
2023-03-31 8:49 ` David Laight
2023-03-31 10:06 ` Kirill A. Shutemov
2023-03-31 13:40 ` Tom Lendacky
2023-03-31 14:09 ` Kirill A. Shutemov
2023-03-31 14:33 ` Tom Lendacky
2023-03-31 15:25 ` Kirill A. Shutemov
2023-03-31 15:50 ` Tom Lendacky
2023-03-31 15:59 ` David Laight
2023-03-31 15:30 ` Dave Hansen [this message]
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