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([172.25.112.68]) by fmsmga001.fm.intel.com with ESMTP; 31 Jul 2023 00:02:13 -0700 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 329a4bd2-2f70-11ee-8613-37d641c3527e DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1690786943; x=1722322943; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=QeZUtDgMAPwFIrdo9TmaG72+ignP6GGIZpxe8B2aw6k=; b=QuUXo2nb07kF44TG969mFLg28G1/4KTubgFPBSjRLmyJ7vTIp0rSbvsl XFiPuxZL4Q/geYa/I2UaJyiFx5mi1CR6naRlvLyukNEd7yXU0y9EYd8Cl Oi3q4c2uSu/JN2B2omLZpu6wAUNAPdtDaaiCezqfsyKCxbQSUCBYTa4n5 6X1Ap+fFj/Guudf6c1cBPJxM1/J+ERuuRmXv8XeCbLsCh1l+2LVfOCd0W o5l/t++z+yxhYff7dPHV2rKgXM+Z4fIFXSW90NT+lyzrer4ZH1i1sGg4p 6aIoeD+57B02bhHgANDn/jGHEkowA0Z9wHBpos2uXM/jDWEdN/9jF+Hro Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10787"; a="371649347" X-IronPort-AV: E=Sophos;i="6.01,244,1684825200"; d="scan'208";a="371649347" X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.01,202,1684825200"; d="scan'208";a="871543474" From: Xin Li To: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org Cc: Jonathan Corbet , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , Andy Lutomirski , Oleg Nesterov , Tony Luck , "K . Y . Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Paolo Bonzini , Wanpeng Li , Vitaly Kuznetsov , Sean Christopherson , Peter Zijlstra , Juergen Gross , Stefano Stabellini , Oleksandr Tyshchenko , Josh Poimboeuf , "Paul E . McKenney" , Catalin Marinas , Randy Dunlap , Steven Rostedt , Kim Phillips , Xin Li , Hyeonggon Yoo <42.hyeyoo@gmail.com>, "Liam R . Howlett" , Sebastian Reichel , "Kirill A . Shutemov" , Suren Baghdasaryan , Pawan Gupta , Jiaxi Chen , Babu Moger , Jim Mattson , Sandipan Das , Lai Jiangshan , Hans de Goede , Reinette Chatre , Daniel Sneddon , Breno Leitao , Nikunj A Dadhania , Brian Gerst , Sami Tolvanen , Alexander Potapenko , Andrew Morton , Arnd Bergmann , "Eric W . Biederman" , Kees Cook , Masami Hiramatsu , Masahiro Yamada , Ze Gao , Fei Li , Conghui , Ashok Raj , "Jason A . Donenfeld" , Mark Rutland , Jacob Pan , Jiapeng Chong , Jane Malalane , David Woodhouse , Boris Ostrovsky , Arnaldo Carvalho de Melo , Yantengsi , Christophe Leroy , Sathvika Vasireddy Subject: [PATCH v9 22/36] x86/fred: Add a double fault entry stub for FRED Date: Sun, 30 Jul 2023 23:33:03 -0700 Message-Id: <20230731063317.3720-23-xin3.li@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230731063317.3720-1-xin3.li@intel.com> References: <20230731063317.3720-1-xin3.li@intel.com> MIME-Version: 1.0 The IDT event delivery of a double fault pushes an error code into the orig_ax member of the pt_regs structure, and the error code is passed as the second argument of its C-handler exc_double_fault(), although the pt_regs structure is already passed as the first argument. The existing IDT double fault asm entry code does the following movq ORIG_RAX(%rsp), %rsi /* get error code into 2nd argument*/ movq $-1, ORIG_RAX(%rsp) /* no syscall to restart */ to set the orig_ax member to -1 just before calling the C-handler. X86_TRAP_TS, X86_TRAP_NP, X86_TRAP_SS, X86_TRAP_GP, X86_TRAP_AC and X86_TRAP_CP are all handled in the same way because the IDT event delivery pushes an error code into their stack frame for them. The commit d99015b1abbad ("x86: move entry_64.S register saving out of the macros") introduced the changes to set orig_ax to -1, but I can't see why. Our tests with FRED seem fine if orig_ax is left unchanged instead of set to -1. It's probably cleaner and simpler to remove the second argument from exc_double_fault() while leave orig_ax unchanged to pass the error code inside the first argument, at least on native x86_64. That would be a separate, pre-FRED, patch. For now just add a double fault entry stub for FRED, which simply calls the existing exc_double_fault(). Tested-by: Shan Kang Signed-off-by: Xin Li --- arch/x86/include/asm/fred.h | 1 + arch/x86/kernel/traps.c | 7 +++++++ 2 files changed, 8 insertions(+) diff --git a/arch/x86/include/asm/fred.h b/arch/x86/include/asm/fred.h index f559dd9dc4f2..bd701ac87528 100644 --- a/arch/x86/include/asm/fred.h +++ b/arch/x86/include/asm/fred.h @@ -116,6 +116,7 @@ DECLARE_FRED_HANDLER(fred_exc_nmi); DECLARE_FRED_HANDLER(fred_exc_debug); DECLARE_FRED_HANDLER(fred_exc_page_fault); DECLARE_FRED_HANDLER(fred_exc_machine_check); +DECLARE_FRED_HANDLER(fred_exc_double_fault); #endif /* __ASSEMBLY__ */ diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index b10464966a81..49dd92458eb0 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -555,6 +555,13 @@ DEFINE_IDTENTRY_DF(exc_double_fault) instrumentation_end(); } +#ifdef CONFIG_X86_FRED +DEFINE_FRED_HANDLER(fred_exc_double_fault) +{ + exc_double_fault(regs, regs->orig_ax); +} +#endif + DEFINE_IDTENTRY(exc_bounds) { if (notify_die(DIE_TRAP, "bounds", regs, 0,