From patchwork Tue Dec 20 06:36:48 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Li, Xin3" X-Patchwork-Id: 13077548 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4798AC10F1E for ; Tue, 20 Dec 2022 07:02:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233555AbiLTHCz (ORCPT ); Tue, 20 Dec 2022 02:02:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53324 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233291AbiLTHBo (ORCPT ); Tue, 20 Dec 2022 02:01:44 -0500 Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1702A15FF8; Mon, 19 Dec 2022 23:01:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1671519699; x=1703055699; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=qQ9Z77NM1zplaDcAHAltOb9XPQ/w7BLCugheNo/3+b4=; b=Syxx1tduIPJWZ1i0y+IVYoj+oRxg4VyQGr76cCkNYeXkCQZNwuFpLFiL p7mp3G7HgaZ6iQdbiWcRMqMAh37Znoi6N8SsA9jAYmrC/NVvcGpy8/3Oq JEpgOVRQfTyxc73WoQ+zXK1Yr6z/5vPxFjp0JE3VtUoKoytSeXEgecNuP +GaOsG6RxJEqUUQg+reL7Nn70pfOLKLE0+/u+57u+zX0u1YvhdbR1cTwE TFWfWzEIZid5RXyb6pxz6qbYvXf22Vk2/NDNyj1kYNI81LFSTPSRGyAMZ zjDrVgzszwU26orL4qjAZq6fdEm+o2GGqcRyoLp2dpfcprXGn14GS8/mw Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10566"; a="302972099" X-IronPort-AV: E=Sophos;i="5.96,258,1665471600"; d="scan'208";a="302972099" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Dec 2022 23:01:17 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10566"; a="644326519" X-IronPort-AV: E=Sophos;i="5.96,258,1665471600"; d="scan'208";a="644326519" Received: from unknown (HELO fred..) ([172.25.112.68]) by orsmga007.jf.intel.com with ESMTP; 19 Dec 2022 23:01:16 -0800 From: Xin Li To: linux-kernel@vger.kernel.org, x86@kernel.org, kvm@vger.kernel.org Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, peterz@infradead.org, andrew.cooper3@citrix.com, seanjc@google.com, pbonzini@redhat.com, ravi.v.shankar@intel.com Subject: [RFC PATCH 22/32] x86/fred: FRED initialization code Date: Mon, 19 Dec 2022 22:36:48 -0800 Message-Id: <20221220063658.19271-23-xin3.li@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20221220063658.19271-1-xin3.li@intel.com> References: <20221220063658.19271-1-xin3.li@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: "H. Peter Anvin (Intel)" The code to initialize FRED when it's available and _not_ disabled. cpu_init_fred_exceptions() is the core function to initialize FRED, which 1. Sets up FRED entrypoints for events happening in ring 0 and 3. 2. Sets up a default stack for event handling. 3. Sets up dedicated event stacks for DB/NMI/MC/DF, equivalent to the IDT IST stacks. 4. Forces 32-bit system calls to use "int $0x80" only. 5. Enables FRED and invalidtes IDT. When the FRED is used, cpu_init_exception_handling() initializes FRED through calling cpu_init_fred_exceptions(), otherwise it sets up TSS IST and loads IDT. As FRED uses the ring 3 FRED entrypoint for SYSCALL and SYSENTER, it skips setting up SYSCALL/SYSENTER related MSRs, e.g., MSR_LSTAR. Signed-off-by: H. Peter Anvin (Intel) Co-developed-by: Xin Li Signed-off-by: Xin Li --- arch/x86/include/asm/fred.h | 14 +++++++ arch/x86/include/asm/traps.h | 2 + arch/x86/kernel/Makefile | 1 + arch/x86/kernel/cpu/common.c | 74 +++++++++++++++++++++++------------- arch/x86/kernel/fred.c | 73 +++++++++++++++++++++++++++++++++++ arch/x86/kernel/irqinit.c | 7 +++- arch/x86/kernel/traps.c | 16 +++++++- 7 files changed, 157 insertions(+), 30 deletions(-) create mode 100644 arch/x86/kernel/fred.c diff --git a/arch/x86/include/asm/fred.h b/arch/x86/include/asm/fred.h index 01678ced5451..b6308e351e14 100644 --- a/arch/x86/include/asm/fred.h +++ b/arch/x86/include/asm/fred.h @@ -97,8 +97,22 @@ DECLARE_FRED_HANDLER(fred_exc_debug); DECLARE_FRED_HANDLER(fred_exc_page_fault); DECLARE_FRED_HANDLER(fred_exc_machine_check); +/* + * The actual assembly entry and exit points + */ +extern __visible void fred_entrypoint_user(void); + +/* + * Initialization + */ +void cpu_init_fred_exceptions(void); +void fred_setup_apic(void); + #endif /* __ASSEMBLY__ */ +#else +#define cpu_init_fred_exceptions() BUG() +#define fred_setup_apic() BUG() #endif /* CONFIG_X86_FRED */ #endif /* ASM_X86_FRED_H */ diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h index 77ffc580e821..963c51e680bd 100644 --- a/arch/x86/include/asm/traps.h +++ b/arch/x86/include/asm/traps.h @@ -56,6 +56,8 @@ void __noreturn handle_stack_overflow(struct pt_regs *regs, void f (struct pt_regs *regs) typedef DECLARE_SYSTEM_INTERRUPT_HANDLER((*system_interrupt_handler)); +system_interrupt_handler get_system_interrupt_handler(unsigned int i); + int exc_raise_irq(struct pt_regs *regs, u32 vector); int external_interrupt(struct pt_regs *regs, unsigned int vector); diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index f901658d9f7c..1d9e669e288b 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -48,6 +48,7 @@ obj-y += process_$(BITS).o signal.o obj-$(CONFIG_COMPAT) += signal_compat.o obj-y += traps.o idt.o irq.o irq_$(BITS).o dumpstack_$(BITS).o obj-y += time.o ioport.o dumpstack.o nmi.o +obj-$(CONFIG_X86_FRED) += fred.o obj-$(CONFIG_MODIFY_LDT_SYSCALL) += ldt.o obj-y += setup.o x86_init.o i8259.o irqinit.o obj-$(CONFIG_JUMP_LABEL) += jump_label.o diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 05a5538052ad..5de68356fe62 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -57,6 +57,7 @@ #include #include #include +#include #include #include #include @@ -2034,28 +2035,6 @@ static void wrmsrl_cstar(unsigned long val) /* May not be marked __init: used by software suspend */ void syscall_init(void) { - wrmsr(MSR_STAR, 0, (__USER32_CS << 16) | __KERNEL_CS); - wrmsrl(MSR_LSTAR, (unsigned long)entry_SYSCALL_64); - -#ifdef CONFIG_IA32_EMULATION - wrmsrl_cstar((unsigned long)entry_SYSCALL_compat); - /* - * This only works on Intel CPUs. - * On AMD CPUs these MSRs are 32-bit, CPU truncates MSR_IA32_SYSENTER_EIP. - * This does not cause SYSENTER to jump to the wrong location, because - * AMD doesn't allow SYSENTER in long mode (either 32- or 64-bit). - */ - wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)__KERNEL_CS); - wrmsrl_safe(MSR_IA32_SYSENTER_ESP, - (unsigned long)(cpu_entry_stack(smp_processor_id()) + 1)); - wrmsrl_safe(MSR_IA32_SYSENTER_EIP, (u64)entry_SYSENTER_compat); -#else - wrmsrl_cstar((unsigned long)ignore_sysret); - wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)GDT_ENTRY_INVALID_SEG); - wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 0ULL); - wrmsrl_safe(MSR_IA32_SYSENTER_EIP, 0ULL); -#endif - /* * Flags to clear on syscall; clear as much as possible * to minimize user space-kernel interference. @@ -2066,6 +2045,41 @@ void syscall_init(void) X86_EFLAGS_IF|X86_EFLAGS_DF|X86_EFLAGS_OF| X86_EFLAGS_IOPL|X86_EFLAGS_NT|X86_EFLAGS_RF| X86_EFLAGS_AC|X86_EFLAGS_ID); + + /* + * The default user and kernel segments + */ + wrmsr(MSR_STAR, 0, (__USER32_CS << 16) | __KERNEL_CS); + + if (cpu_feature_enabled(X86_FEATURE_FRED)) { + /* Both sysexit and sysret cause #UD when FRED is enabled */ + wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)GDT_ENTRY_INVALID_SEG); + wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 0ULL); + wrmsrl_safe(MSR_IA32_SYSENTER_EIP, 0ULL); + } else { + wrmsrl(MSR_LSTAR, (unsigned long)entry_SYSCALL_64); + +#ifdef CONFIG_IA32_EMULATION + wrmsrl_cstar((unsigned long)entry_SYSCALL_compat); + /* + * This only works on Intel CPUs. + * On AMD CPUs these MSRs are 32-bit, CPU truncates + * MSR_IA32_SYSENTER_EIP. + * This does not cause SYSENTER to jump to the wrong + * location, because AMD doesn't allow SYSENTER in + * long mode (either 32- or 64-bit). + */ + wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)__KERNEL_CS); + wrmsrl_safe(MSR_IA32_SYSENTER_ESP, + (unsigned long)(cpu_entry_stack(smp_processor_id()) + 1)); + wrmsrl_safe(MSR_IA32_SYSENTER_EIP, (u64)entry_SYSENTER_compat); +#else + wrmsrl_cstar((unsigned long)ignore_sysret); + wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)GDT_ENTRY_INVALID_SEG); + wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 0ULL); + wrmsrl_safe(MSR_IA32_SYSENTER_EIP, 0ULL); +#endif + } } #else /* CONFIG_X86_64 */ @@ -2214,18 +2228,24 @@ void cpu_init_exception_handling(void) /* paranoid_entry() gets the CPU number from the GDT */ setup_getcpu(cpu); - /* IST vectors need TSS to be set up. */ - tss_setup_ist(tss); + /* Set up the TSS */ tss_setup_io_bitmap(tss); set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss); - load_TR_desc(); /* GHCB needs to be setup to handle #VC. */ setup_ghcb(); - /* Finally load the IDT */ - load_current_idt(); + if (cpu_feature_enabled(X86_FEATURE_FRED)) { + /* Set up FRED exception handling */ + cpu_init_fred_exceptions(); + } else { + /* IST vectors need TSS to be set up. */ + tss_setup_ist(tss); + + /* Finally load the IDT */ + load_current_idt(); + } } /* diff --git a/arch/x86/kernel/fred.c b/arch/x86/kernel/fred.c new file mode 100644 index 000000000000..827b58fd98d4 --- /dev/null +++ b/arch/x86/kernel/fred.c @@ -0,0 +1,73 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#include +#include +#include +#include /* For cr4_set_bits() */ +#include + +/* + * Initialize FRED on this CPU. This cannot be __init as it is called + * during CPU hotplug. + */ +void cpu_init_fred_exceptions(void) +{ + wrmsrl(MSR_IA32_FRED_CONFIG, + FRED_CONFIG_ENTRYPOINT(fred_entrypoint_user) | + FRED_CONFIG_REDZONE(8) | /* Reserve for CALL emulation */ + FRED_CONFIG_INT_STKLVL(0)); + + wrmsrl(MSR_IA32_FRED_STKLVLS, + FRED_STKLVL(X86_TRAP_DB, 1) | + FRED_STKLVL(X86_TRAP_NMI, 2) | + FRED_STKLVL(X86_TRAP_MC, 2) | + FRED_STKLVL(X86_TRAP_DF, 3)); + + /* The FRED equivalents to IST stacks... */ + wrmsrl(MSR_IA32_FRED_RSP1, __this_cpu_ist_top_va(DB)); + wrmsrl(MSR_IA32_FRED_RSP2, __this_cpu_ist_top_va(NMI)); + wrmsrl(MSR_IA32_FRED_RSP3, __this_cpu_ist_top_va(DF)); + + /* Not used with FRED */ + wrmsrl(MSR_LSTAR, 0ULL); + wrmsrl(MSR_CSTAR, 0ULL); + wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)GDT_ENTRY_INVALID_SEG); + wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 0ULL); + wrmsrl_safe(MSR_IA32_SYSENTER_EIP, 0ULL); + + /* Enable FRED */ + cr4_set_bits(X86_CR4_FRED); + idt_invalidate(); /* Any further IDT use is a bug */ + + /* Use int $0x80 for 32-bit system calls in FRED mode */ + setup_clear_cpu_cap(X86_FEATURE_SYSENTER32); + setup_clear_cpu_cap(X86_FEATURE_SYSCALL32); +} + +/* + * Initialize system vectors from a FRED perspective, so + * lapic_assign_system_vectors() can do its job. + */ +void __init fred_setup_apic(void) +{ + int i; + + for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++) + set_bit(i, system_vectors); + + /* + * Don't set the non assigned system vectors in the + * system_vectors bitmap. Otherwise they show up in + * /proc/interrupts. + */ +#ifdef CONFIG_SMP + set_bit(IRQ_MOVE_CLEANUP_VECTOR, system_vectors); +#endif + + for (i = 0; i < NR_SYSTEM_VECTORS; i++) { + if (get_system_interrupt_handler(i) != NULL) { + set_bit(i + FIRST_SYSTEM_VECTOR, system_vectors); + } + } + + /* The rest are fair game... */ +} diff --git a/arch/x86/kernel/irqinit.c b/arch/x86/kernel/irqinit.c index beb1bada1b0a..bb59661f0278 100644 --- a/arch/x86/kernel/irqinit.c +++ b/arch/x86/kernel/irqinit.c @@ -28,6 +28,7 @@ #include #include #include +#include #include /* @@ -94,7 +95,11 @@ void __init native_init_IRQ(void) /* Execute any quirks before the call gates are initialised: */ x86_init.irqs.pre_vector_init(); - idt_setup_apic_and_irq_gates(); + if (cpu_feature_enabled(X86_FEATURE_FRED)) + fred_setup_apic(); + else + idt_setup_apic_and_irq_gates(); + lapic_assign_system_vectors(); if (!acpi_ioapic && !of_ioapic && nr_legacy_irqs()) { diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index b0ee83bab9e6..36a15df9b5e5 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -1518,12 +1518,21 @@ static system_interrupt_handler system_interrupt_handlers[NR_SYSTEM_VECTORS] = { #undef SYSV +system_interrupt_handler get_system_interrupt_handler(unsigned int i) +{ + if (i >= NR_SYSTEM_VECTORS) + return NULL; + + return system_interrupt_handlers[i]; +} + void __init install_system_interrupt_handler(unsigned int n, const void *asm_addr, const void *addr) { BUG_ON(n < FIRST_SYSTEM_VECTOR); system_interrupt_handlers[n - FIRST_SYSTEM_VECTOR] = (system_interrupt_handler)addr; - alloc_intr_gate(n, asm_addr); + if (!cpu_feature_enabled(X86_FEATURE_FRED)) + alloc_intr_gate(n, asm_addr); } #ifndef CONFIG_X86_LOCAL_APIC @@ -1591,7 +1600,10 @@ void __init trap_init(void) /* Initialize TSS before setting up traps so ISTs work */ cpu_init_exception_handling(); + /* Setup traps as cpu_init() might #GP */ - idt_setup_traps(); + if (!cpu_feature_enabled(X86_FEATURE_FRED)) + idt_setup_traps(); + cpu_init(); }