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([172.25.112.68]) by fmsmga001.fm.intel.com with ESMTP; 31 Jul 2023 00:02:05 -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: 2e47e567-2f70-11ee-b254-6b7b168915f2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1690786935; x=1722322935; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=YTgEgmA3f1uzY8PacyZ6XmpZcGIgDW5/dB0vDrivilc=; b=fnppCNQlR8OFiIsXmxCPcLsvBqp/aiHqB5+XNK4UjDRsFJdcVecVBV8S lJ4wW293gtb5RnIyZa4CjPTRxmu9XN0M3djYCvrU9d3nKRcd2GJAYrgiA K5OyaPyG0TrymSos449pgtkV7r9WMLtRMkGD6zeURTLpb90DA7YhdNoTx SJThy+Bi3L/XhuAB0FHbYZLUz9NGt+ME7Podi/bNSW6nxXPn5y+EIeYR6 OVLgqBA3axyFB1N8NdYEsVxWqme5wfR2MzbDNTRnCjfP2Ht2oK4jgLdcI Dmz/Z5B+z3dV785uJc4h1GPXLXtRC0RIA0GdDHPJfns1w3z9jW4UEJ7bQ g==; X-IronPort-AV: E=McAfee;i="6600,9927,10787"; a="371649101" X-IronPort-AV: E=Sophos;i="6.01,244,1684825200"; d="scan'208";a="371649101" X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.01,202,1684825200"; d="scan'208";a="871543430" 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 15/36] x86/fred: No ESPFIX needed when FRED is enabled Date: Sun, 30 Jul 2023 23:32:56 -0700 Message-Id: <20230731063317.3720-16-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 From: "H. Peter Anvin (Intel)" Because FRED always restores the full value of %rsp, ESPFIX is no longer needed when it's enabled. Signed-off-by: H. Peter Anvin (Intel) Tested-by: Shan Kang Signed-off-by: Xin Li --- arch/x86/kernel/espfix_64.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/kernel/espfix_64.c b/arch/x86/kernel/espfix_64.c index 16f9814c9be0..48d133a54f45 100644 --- a/arch/x86/kernel/espfix_64.c +++ b/arch/x86/kernel/espfix_64.c @@ -106,6 +106,10 @@ void __init init_espfix_bsp(void) pgd_t *pgd; p4d_t *p4d; + /* FRED systems don't need ESPFIX */ + if (cpu_feature_enabled(X86_FEATURE_FRED)) + return; + /* Install the espfix pud into the kernel page directory */ pgd = &init_top_pgt[pgd_index(ESPFIX_BASE_ADDR)]; p4d = p4d_alloc(&init_mm, pgd, ESPFIX_BASE_ADDR); @@ -129,6 +133,10 @@ void init_espfix_ap(int cpu) void *stack_page; pteval_t ptemask; + /* FRED systems don't need ESPFIX */ + if (cpu_feature_enabled(X86_FEATURE_FRED)) + return; + /* We only have to do this once... */ if (likely(per_cpu(espfix_stack, cpu))) return; /* Already initialized */