diff options
| author | Xin Li (Intel) <xin@zytor.com> | 2024-07-09 08:40:46 -0700 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2024-08-13 21:59:21 +0200 |
| commit | 989b5cfaa7b6054f4e1bde914470ee091c23e6a5 (patch) | |
| tree | e6429ce91b420bea7b6f2724cf6aa01136cf79ea /arch/x86/kernel/cpu/common.c | |
| parent | 7c626ce4bae1ac14f60076d00eafe71af30450ba (diff) | |
x86/fred: Parse cmdline param "fred=" in cpu_parse_early_param()
Depending on whether FRED is enabled, sysvec_install() installs a system
interrupt handler into either into FRED's system vector dispatch table or
into the IDT.
However FRED can be disabled later in trap_init(), after sysvec_install()
has been invoked already; e.g., the HYPERVISOR_CALLBACK_VECTOR handler is
registered with sysvec_install() in kvm_guest_init(), which is called in
setup_arch() but way before trap_init().
IOW, there is a gap between FRED is available and available but disabled.
As a result, when FRED is available but disabled, early sysvec_install()
invocations fail to install the IDT handler resulting in spurious
interrupts.
Fix it by parsing cmdline param "fred=" in cpu_parse_early_param() to
ensure that FRED is disabled before the first sysvec_install() incovations.
Fixes: 3810da12710a ("x86/fred: Add a fred= cmdline param")
Reported-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Xin Li (Intel) <xin@zytor.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240709154048.3543361-2-xin@zytor.com
Diffstat (limited to 'arch/x86/kernel/cpu/common.c')
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index d4e539d4e158..10a5402d8297 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1510,6 +1510,11 @@ static void __init cpu_parse_early_param(void) if (cmdline_find_option_bool(boot_command_line, "nousershstk")) setup_clear_cpu_cap(X86_FEATURE_USER_SHSTK); + /* Minimize the gap between FRED is available and available but disabled. */ + arglen = cmdline_find_option(boot_command_line, "fred", arg, sizeof(arg)); + if (arglen != 2 || strncmp(arg, "on", 2)) + setup_clear_cpu_cap(X86_FEATURE_FRED); + arglen = cmdline_find_option(boot_command_line, "clearcpuid", arg, sizeof(arg)); if (arglen <= 0) return; |