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([172.25.112.68]) by fmsmga006.fm.intel.com with ESMTP; 01 Aug 2023 02:02:01 -0700 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 , 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 RESEND v9 12/36] x86/fred: Update MSR_IA32_FRED_RSP0 during task switch Date: Tue, 1 Aug 2023 01:32:54 -0700 Message-Id: <20230801083318.8363-13-xin3.li@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230801083318.8363-1-xin3.li@intel.com> References: <20230801083318.8363-1-xin3.li@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-edac@vger.kernel.org From: "H. Peter Anvin (Intel)" MSR_IA32_FRED_RSP0 is used during ring 3 event delivery, and needs to be updated to point to the top of next task stack during task switch. Update MSR_IA32_FRED_RSP0 with WRMSR instruction for now, and will use WRMSRNS/WRMSRLIST for performance once it gets upstreamed. Signed-off-by: H. Peter Anvin (Intel) Tested-by: Shan Kang Signed-off-by: Xin Li --- arch/x86/include/asm/switch_to.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/switch_to.h b/arch/x86/include/asm/switch_to.h index f42dbf17f52b..6c911fd400b2 100644 --- a/arch/x86/include/asm/switch_to.h +++ b/arch/x86/include/asm/switch_to.h @@ -70,9 +70,16 @@ static inline void update_task_stack(struct task_struct *task) #ifdef CONFIG_X86_32 this_cpu_write(cpu_tss_rw.x86_tss.sp1, task->thread.sp0); #else - /* Xen PV enters the kernel on the thread stack. */ - if (cpu_feature_enabled(X86_FEATURE_XENPV)) + if (cpu_feature_enabled(X86_FEATURE_FRED)) { + /* + * Will use WRMSRNS/WRMSRLIST for performance once it's upstreamed. + */ + wrmsrl(MSR_IA32_FRED_RSP0, + (unsigned long)task_stack_page(task) + THREAD_SIZE); + } else if (cpu_feature_enabled(X86_FEATURE_XENPV)) { + /* Xen PV enters the kernel on the thread stack. */ load_sp0(task_top_of_stack(task)); + } #endif } -- 2.34.1