From patchwork Tue Dec 5 10:50:20 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Li, Xin3" X-Patchwork-Id: 13480080 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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0F2E9C4167B for ; Tue, 5 Dec 2023 11:33:26 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.647648.1011110 (Exim 4.92) (envelope-from ) id 1rATfq-0006nZ-AB; Tue, 05 Dec 2023 11:33:10 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 647648.1011110; Tue, 05 Dec 2023 11:33:10 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1rATfq-0006nS-68; Tue, 05 Dec 2023 11:33:10 +0000 Received: by outflank-mailman (input) for mailman id 647648; Tue, 05 Dec 2023 11:33:08 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1rATUr-0003dP-VP for xen-devel@lists.xenproject.org; Tue, 05 Dec 2023 11:21:49 +0000 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.12]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id 74bba901-9360-11ee-9b0f-b553b5be7939; Tue, 05 Dec 2023 12:21:38 +0100 (CET) Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orvoesa104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Dec 2023 03:21:27 -0800 Received: from unknown (HELO fred..) ([172.25.112.68]) by fmsmga006.fm.intel.com with ESMTP; 05 Dec 2023 03:21:25 -0800 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: 74bba901-9360-11ee-9b0f-b553b5be7939 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1701775299; x=1733311299; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=p+DpQXfFjluhEPpBgGqFegRQUmj2AdYX7lnZ9lGR9vg=; b=TI+bMRht9g89dUAdmHviwWlrkw4v/mjOpYCuCmid7+QnETIhps+bgRqL KuxU4xl1ONqRMoJCXvxCDY5DyCT2k8PzJyReL5hP4C6q7xIo4c1uyByk6 I1cJFT00UNeKTtHuv/yKCmT3H8ZJKp52BbYontaKQd606P8M9as2oIYfl gNGQBuO1hQx+G0oQAU9it/UR049Jvs6dWTEDtmz6BHKpV5fkkJBdRoTUJ PSJNCF7MRgMlYYEPpdCJFMK5uloQQ9VeQXDIV5rYHGZ0xIbrYhOgP4AzF LnrZHOGkXZ/UxAz0TQ/mn1xrNpz13V7AqXzs5yD7+TKKNigxq5jkvju92 A==; X-IronPort-AV: E=McAfee;i="6600,9927,10914"; a="942682" X-IronPort-AV: E=Sophos;i="6.04,252,1695711600"; d="scan'208";a="942682" X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10914"; a="1018193009" X-IronPort-AV: E=Sophos;i="6.04,252,1695711600"; d="scan'208";a="1018193009" 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: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, luto@kernel.org, pbonzini@redhat.com, seanjc@google.com, peterz@infradead.org, jgross@suse.com, ravi.v.shankar@intel.com, mhiramat@kernel.org, andrew.cooper3@citrix.com, jiangshanlai@gmail.com, nik.borisov@suse.com, shan.kang@intel.com Subject: [PATCH v13 31/35] x86/entry: Add fred_entry_from_kvm() for VMX to handle IRQ/NMI Date: Tue, 5 Dec 2023 02:50:20 -0800 Message-ID: <20231205105030.8698-32-xin3.li@intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231205105030.8698-1-xin3.li@intel.com> References: <20231205105030.8698-1-xin3.li@intel.com> MIME-Version: 1.0 In IRQ/NMI induced VM exits, KVM VMX needs to execute the respective handlers, which requires the software to create a FRED stack frame, and use it to invoke the handlers. Add fred_irq_entry_from_kvm() for this job. Export fred_entry_from_kvm() because VMX can be compiled as a module. Suggested-by: Sean Christopherson Suggested-by: Thomas Gleixner Tested-by: Shan Kang Signed-off-by: Xin Li --- Changes since v10: * Better explain the reason why no need to check current stack level (Paolo Bonzini). Changes since v9: * Shove the whole thing into arch/x86/entry/entry_64_fred.S for invoking external_interrupt() and fred_exc_nmi() (Sean Christopherson). * Correct and improve a few comments (Sean Christopherson). * Merge the two IRQ/NMI asm entries into one as it's fine to invoke noinstr code from regular code (Thomas Gleixner). * Setup the long mode and NMI flags in the augmented SS field of FRED stack frame in C instead of asm (Thomas Gleixner). * Add UNWIND_HINT_{SAVE,RESTORE} to get rid of the warning: "objtool: asm_fred_entry_from_kvm+0x0: unreachable instruction" (Peter Zijlstra). Changes since v8: * Add a new macro VMX_DO_FRED_EVENT_IRQOFF for FRED instead of refactoring VMX_DO_EVENT_IRQOFF (Sean Christopherson). * Do NOT use a trampoline, just LEA+PUSH the return RIP, PUSH the error code, and jump to the FRED kernel entry point for NMI or call external_interrupt() for IRQs (Sean Christopherson). * Call external_interrupt() only when FRED is enabled, and convert the non-FRED handling to external_interrupt() after FRED lands (Sean Christopherson). --- arch/x86/entry/entry_64_fred.S | 77 ++++++++++++++++++++++++++++++++++ arch/x86/entry/entry_fred.c | 14 +++++++ arch/x86/include/asm/fred.h | 18 ++++++++ 3 files changed, 109 insertions(+) diff --git a/arch/x86/entry/entry_64_fred.S b/arch/x86/entry/entry_64_fred.S index d1c2fc4af8ae..eedf98de7538 100644 --- a/arch/x86/entry/entry_64_fred.S +++ b/arch/x86/entry/entry_64_fred.S @@ -3,8 +3,11 @@ * The actual FRED entry points. */ +#include + #include #include +#include #include "calling.h" @@ -54,3 +57,77 @@ SYM_CODE_START_NOALIGN(asm_fred_entrypoint_kernel) FRED_EXIT ERETS SYM_CODE_END(asm_fred_entrypoint_kernel) + +#if IS_ENABLED(CONFIG_KVM_INTEL) +SYM_FUNC_START(asm_fred_entry_from_kvm) + push %rbp + mov %rsp, %rbp + + UNWIND_HINT_SAVE + + /* + * Both IRQ and NMI from VMX can be handled on current task stack + * because there is no need to protect from reentrancy and the call + * stack leading to this helper is effectively constant and shallow + * (relatively speaking). Do the same when FRED is active, i.e., no + * need to check current stack level for a stack switch. + * + * Emulate the FRED-defined redzone and stack alignment. + */ + sub $(FRED_CONFIG_REDZONE_AMOUNT << 6), %rsp + and $FRED_STACK_FRAME_RSP_MASK, %rsp + + /* + * Start to push a FRED stack frame, which is always 64 bytes: + * + * +--------+-----------------+ + * | Bytes | Usage | + * +--------+-----------------+ + * | 63:56 | Reserved | + * | 55:48 | Event Data | + * | 47:40 | SS + Event Info | + * | 39:32 | RSP | + * | 31:24 | RFLAGS | + * | 23:16 | CS + Aux Info | + * | 15:8 | RIP | + * | 7:0 | Error Code | + * +--------+-----------------+ + */ + push $0 /* Reserved, must be 0 */ + push $0 /* Event data, 0 for IRQ/NMI */ + push %rdi /* fred_ss handed in by the caller */ + push %rbp + pushf + mov $__KERNEL_CS, %rax + push %rax + + /* + * Unlike the IDT event delivery, FRED _always_ pushes an error code + * after pushing the return RIP, thus the CALL instruction CANNOT be + * used here to push the return RIP, otherwise there is no chance to + * push an error code before invoking the IRQ/NMI handler. + * + * Use LEA to get the return RIP and push it, then push an error code. + */ + lea 1f(%rip), %rax + push %rax /* Return RIP */ + push $0 /* Error code, 0 for IRQ/NMI */ + + PUSH_AND_CLEAR_REGS clear_bp=0 unwind_hint=0 + movq %rsp, %rdi /* %rdi -> pt_regs */ + call __fred_entry_from_kvm /* Call the C entry point */ + POP_REGS + ERETS +1: + /* + * Objtool doesn't understand what ERETS does, this hint tells it that + * yes, we'll reach here and with what stack state. A save/restore pair + * isn't strictly needed, but it's the simplest form. + */ + UNWIND_HINT_RESTORE + pop %rbp + RET + +SYM_FUNC_END(asm_fred_entry_from_kvm) +EXPORT_SYMBOL_GPL(asm_fred_entry_from_kvm); +#endif diff --git a/arch/x86/entry/entry_fred.c b/arch/x86/entry/entry_fred.c index e80e3efbc057..3e33a4ab4624 100644 --- a/arch/x86/entry/entry_fred.c +++ b/arch/x86/entry/entry_fred.c @@ -242,3 +242,17 @@ __visible noinstr void fred_entry_from_kernel(struct pt_regs *regs) return fred_bad_type(regs, error_code); } } + +#if IS_ENABLED(CONFIG_KVM_INTEL) +__visible noinstr void __fred_entry_from_kvm(struct pt_regs *regs) +{ + switch (regs->fred_ss.type) { + case EVENT_TYPE_EXTINT: + return fred_extint(regs); + case EVENT_TYPE_NMI: + return fred_exc_nmi(regs); + default: + WARN_ON_ONCE(1); + } +} +#endif diff --git a/arch/x86/include/asm/fred.h b/arch/x86/include/asm/fred.h index 16a64ffecbf8..2fa9f34e5c95 100644 --- a/arch/x86/include/asm/fred.h +++ b/arch/x86/include/asm/fred.h @@ -9,6 +9,7 @@ #include #include +#include /* * FRED event return instruction opcodes for ERET{S,U}; supported in @@ -62,12 +63,29 @@ static __always_inline unsigned long fred_event_data(struct pt_regs *regs) void asm_fred_entrypoint_user(void); void asm_fred_entrypoint_kernel(void); +void asm_fred_entry_from_kvm(struct fred_ss); __visible void fred_entry_from_user(struct pt_regs *regs); __visible void fred_entry_from_kernel(struct pt_regs *regs); +__visible void __fred_entry_from_kvm(struct pt_regs *regs); + +/* Can be called from noinstr code, thus __always_inline */ +static __always_inline void fred_entry_from_kvm(unsigned int type, unsigned int vector) +{ + struct fred_ss ss = { + .ss =__KERNEL_DS, + .type = type, + .vector = vector, + .nmi = type == EVENT_TYPE_NMI, + .lm = 1, + }; + + asm_fred_entry_from_kvm(ss); +} #else /* CONFIG_X86_FRED */ static __always_inline unsigned long fred_event_data(struct pt_regs *regs) { return 0; } +static __always_inline void fred_entry_from_kvm(unsigned int type, unsigned int vector) { } #endif /* CONFIG_X86_FRED */ #endif /* !__ASSEMBLY__ */