[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-ID: <20240709154048.3543361-1-xin@zytor.com>
Date: Tue, 9 Jul 2024 08:40:45 -0700
From: "Xin Li (Intel)" <xin@...or.com>
To: linux-kernel@...r.kernel.org
Cc: hpa@...or.com, tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
dave.hansen@...ux.intel.com, x86@...nel.org, peterz@...radead.org,
andrew.cooper3@...rix.com, nik.borisov@...e.com,
houwenlong.hwl@...group.com
Subject: [PATCH v2 0/3] Enable FRED earlier
Wenlong Hou from Ant group reported two problems during the FRED
initialization:
https://lore.kernel.org/lkml/cover.1718972598.git.houwenlong.hwl@antgroup.com/
The first problem is that spurious_interrupt() gets called on the
HYPERVISOR_CALLBACK_VECTOR vector. Because kvm_guest_init(), being
executed way before trap_init() in which it is decided that whether
FRED will be enabled or not, calls sysvec_install() to install
HYPERVISOR_CALLBACK_VECTOR's interrupt handler into FRED system
vector dispatch table or IDT depending on whether FRED is enabled.
The other problem is that the #PF handler gets a wrong faulting
address from the stack instead of CR2 before FRED is enabled.
Because the #PF handler fetches its faulting addresss from the
stack or CR2 based on whether FRED is available rather than active.
This patchset fixes the 2 problems with suggestions from tglx:
1) Parse cmdline param "fred=" in cpu_parse_early_param() to
minimize the gap mentioned above, before kvm_guest_init().
2) Enable FRED right after init_mem_mapping() to switch to FRED
from early IDT ASAP, avoid intermediately using the IDT #PF
handler.
Link to v1:
https://lore.kernel.org/lkml/20240703085426.274801-1-xin@zytor.com/
Changes since v1:
* Drop the patch that changes wrmsrl() to wrmsrns().
* Use strncmp() instead of strcmp().
Xin Li (Intel) (3):
x86/fred: Parse cmdline param "fred=" in cpu_parse_early_param()
x86/fred: Split FRED RSP initialization into a separate function
x86/fred: Enable FRED right after init_mem_mapping()
arch/x86/include/asm/fred.h | 2 ++
arch/x86/kernel/cpu/common.c | 9 ++++++---
arch/x86/kernel/fred.c | 28 +++++++++++++++++++---------
arch/x86/kernel/setup.c | 11 ++++++++++-
arch/x86/kernel/smpboot.c | 6 ++++++
arch/x86/kernel/traps.c | 30 ++++--------------------------
6 files changed, 47 insertions(+), 39 deletions(-)
base-commit: aa9d8caba6e40b0b02a6f2b5f2bd9177cd76cacf
--
2.45.2
Powered by blists - more mailing lists