From patchwork Wed Jul 8 19:51:57 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Gleixner X-Patchwork-Id: 11652409 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 37BFF913 for ; Wed, 8 Jul 2020 19:54:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1C2A6207BB for ; Wed, 8 Jul 2020 19:54:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="XfStOCYT"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="BUkiJ1yY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726763AbgGHTyI (ORCPT ); Wed, 8 Jul 2020 15:54:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43998 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725446AbgGHTxo (ORCPT ); Wed, 8 Jul 2020 15:53:44 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A99B4C061A0B; Wed, 8 Jul 2020 12:53:43 -0700 (PDT) Message-Id: <20200708195322.037311579@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1594238022; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: references:references; bh=L8WFl/qe3bcU20FmleRqAp3Ck6NxoIyNeaRZ5GSxwe4=; b=XfStOCYTMjEEcEia8QQfb1042hqloaB38lQS7WlsinhyyhUFIWoiZ9VhiLnLrdbeQte/7O hMu5HJ8mDj60YbebjR28RGJqvxFv/8tHs6RmLD5m09BmjfwjOJysLReSlEXIPSG7dQ1+/l WrCkyANpnrB0sdnDc/KRLYNrJrDMCzhjL1Oh7PVVIA9x+leep0JQvFH6ppkc7/YQxSCC3I LYOSdCqbgNC2SNmaPlMhlw57uy7En5896yGzyEDdwFrefcm77bfXMDMYHmzk6RtS1Z65/A weabWqpMFEfUFXDJI1yHQLNb3XwEfQUA/25C8quJtCPRzN6j59PFgRGU0DByMQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1594238022; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: references:references; bh=L8WFl/qe3bcU20FmleRqAp3Ck6NxoIyNeaRZ5GSxwe4=; b=BUkiJ1yYbCQkbC6EL40F2W8tcrxzg/88DJ8ZzOcJVRulQtEThm4BpQs9vw+eNiqtivIsGA y+n9Q9q+BIjdoTCw== Date: Wed, 08 Jul 2020 21:51:57 +0200 From: Thomas Gleixner To: LKML Cc: x86@kernel.org, Paolo Bonzini , kvm@vger.kernel.org, Alexandre Chartre , Peter Zijlstra , Juergen Gross Subject: [patch V2 4/7] x86/kvm/vmx: Move guest enter/exit into .noinstr.text References: <20200708195153.746357686@linutronix.de> MIME-Version: 1.0 Content-transfer-encoding: 8-bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Thomas Gleixner Move the functions which are inside the RCU off region into the non-instrumentable text section. Signed-off-by: Thomas Gleixner Reviewed-by: Alexandre Chartre Acked-by: Peter Zijlstra Acked-by: Paolo Bonzini --- arch/x86/include/asm/hardirq.h | 4 - arch/x86/include/asm/kvm_host.h | 8 ++ arch/x86/kvm/vmx/ops.h | 4 + arch/x86/kvm/vmx/vmenter.S | 5 + arch/x86/kvm/vmx/vmx.c | 111 ++++++++++++++++++++++------------------ arch/x86/kvm/x86.c | 2 6 files changed, 81 insertions(+), 53 deletions(-) --- a/arch/x86/include/asm/hardirq.h +++ b/arch/x86/include/asm/hardirq.h @@ -67,12 +67,12 @@ static inline void kvm_set_cpu_l1tf_flus __this_cpu_write(irq_stat.kvm_cpu_l1tf_flush_l1d, 1); } -static inline void kvm_clear_cpu_l1tf_flush_l1d(void) +static __always_inline void kvm_clear_cpu_l1tf_flush_l1d(void) { __this_cpu_write(irq_stat.kvm_cpu_l1tf_flush_l1d, 0); } -static inline bool kvm_get_cpu_l1tf_flush_l1d(void) +static __always_inline bool kvm_get_cpu_l1tf_flush_l1d(void) { return __this_cpu_read(irq_stat.kvm_cpu_l1tf_flush_l1d); } --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1636,7 +1636,15 @@ asmlinkage void kvm_spurious_fault(void) insn "\n\t" \ "jmp 668f \n\t" \ "667: \n\t" \ + "1: \n\t" \ + ".pushsection .discard.instr_begin \n\t" \ + ".long 1b - . \n\t" \ + ".popsection \n\t" \ "call kvm_spurious_fault \n\t" \ + "1: \n\t" \ + ".pushsection .discard.instr_end \n\t" \ + ".long 1b - . \n\t" \ + ".popsection \n\t" \ "668: \n\t" \ _ASM_EXTABLE(666b, 667b) --- a/arch/x86/kvm/vmx/ops.h +++ b/arch/x86/kvm/vmx/ops.h @@ -146,7 +146,9 @@ do { \ : : op1 : "cc" : error, fault); \ return; \ error: \ + instrumentation_begin(); \ insn##_error(error_args); \ + instrumentation_end(); \ return; \ fault: \ kvm_spurious_fault(); \ @@ -161,7 +163,9 @@ do { \ : : op1, op2 : "cc" : error, fault); \ return; \ error: \ + instrumentation_begin(); \ insn##_error(error_args); \ + instrumentation_end(); \ return; \ fault: \ kvm_spurious_fault(); \ --- a/arch/x86/kvm/vmx/vmenter.S +++ b/arch/x86/kvm/vmx/vmenter.S @@ -27,7 +27,7 @@ #define VCPU_R15 __VCPU_REGS_R15 * WORD_SIZE #endif - .text +.section .noinstr.text, "ax" /** * vmx_vmenter - VM-Enter the current loaded VMCS @@ -234,6 +234,9 @@ SYM_FUNC_START(__vmx_vcpu_run) jmp 1b SYM_FUNC_END(__vmx_vcpu_run) + +.section .text, "ax" + /** * vmread_error_trampoline - Trampoline from inline asm to vmread_error() * @field: VMCS field encoding that failed --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6113,7 +6113,7 @@ static int vmx_handle_exit(struct kvm_vc * information but as all relevant affected CPUs have 32KiB L1D cache size * there is no point in doing so. */ -static void vmx_l1d_flush(struct kvm_vcpu *vcpu) +static noinstr void vmx_l1d_flush(struct kvm_vcpu *vcpu) { int size = PAGE_SIZE << L1D_CACHE_ORDER; @@ -6146,7 +6146,7 @@ static void vmx_l1d_flush(struct kvm_vcp vcpu->stat.l1d_flush++; if (static_cpu_has(X86_FEATURE_FLUSH_L1D)) { - wrmsrl(MSR_IA32_FLUSH_CMD, L1D_FLUSH); + native_wrmsrl(MSR_IA32_FLUSH_CMD, L1D_FLUSH); return; } @@ -6632,7 +6632,7 @@ static void vmx_update_hv_timer(struct k } } -void vmx_update_host_rsp(struct vcpu_vmx *vmx, unsigned long host_rsp) +void noinstr vmx_update_host_rsp(struct vcpu_vmx *vmx, unsigned long host_rsp) { if (unlikely(host_rsp != vmx->loaded_vmcs->host_state.rsp)) { vmx->loaded_vmcs->host_state.rsp = host_rsp; @@ -6654,6 +6654,63 @@ static fastpath_t vmx_exit_handlers_fast bool __vmx_vcpu_run(struct vcpu_vmx *vmx, unsigned long *regs, bool launched); +static noinstr void vmx_vcpu_enter_exit(struct kvm_vcpu *vcpu, + struct vcpu_vmx *vmx) +{ + /* + * VMENTER enables interrupts (host state), but the kernel state is + * interrupts disabled when this is invoked. Also tell RCU about + * it. This is the same logic as for exit_to_user_mode(). + * + * This ensures that e.g. latency analysis on the host observes + * guest mode as interrupt enabled. + * + * guest_enter_irqoff() informs context tracking about the + * transition to guest mode and if enabled adjusts RCU state + * accordingly. + */ + instrumentation_begin(); + trace_hardirqs_on_prepare(); + lockdep_hardirqs_on_prepare(CALLER_ADDR0); + instrumentation_end(); + + guest_enter_irqoff(); + lockdep_hardirqs_on(CALLER_ADDR0); + + /* L1D Flush includes CPU buffer clear to mitigate MDS */ + if (static_branch_unlikely(&vmx_l1d_should_flush)) + vmx_l1d_flush(vcpu); + else if (static_branch_unlikely(&mds_user_clear)) + mds_clear_cpu_buffers(); + + if (vcpu->arch.cr2 != read_cr2()) + write_cr2(vcpu->arch.cr2); + + vmx->fail = __vmx_vcpu_run(vmx, (unsigned long *)&vcpu->arch.regs, + vmx->loaded_vmcs->launched); + + vcpu->arch.cr2 = read_cr2(); + + /* + * VMEXIT disables interrupts (host state), but tracing and lockdep + * have them in state 'on' as recorded before entering guest mode. + * Same as enter_from_user_mode(). + * + * guest_exit_irqoff() restores host context and reinstates RCU if + * enabled and required. + * + * This needs to be done before the below as native_read_msr() + * contains a tracepoint and x86_spec_ctrl_restore_host() calls + * into world and some more. + */ + lockdep_hardirqs_off(CALLER_ADDR0); + guest_exit_irqoff(); + + instrumentation_begin(); + trace_hardirqs_off_finish(); + instrumentation_end(); +} + static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu) { fastpath_t exit_fastpath; @@ -6728,52 +6785,8 @@ static fastpath_t vmx_vcpu_run(struct kv */ x86_spec_ctrl_set_guest(vmx->spec_ctrl, 0); - /* - * VMENTER enables interrupts (host state), but the kernel state is - * interrupts disabled when this is invoked. Also tell RCU about - * it. This is the same logic as for exit_to_user_mode(). - * - * This ensures that e.g. latency analysis on the host observes - * guest mode as interrupt enabled. - * - * guest_enter_irqoff() informs context tracking about the - * transition to guest mode and if enabled adjusts RCU state - * accordingly. - */ - trace_hardirqs_on_prepare(); - lockdep_hardirqs_on_prepare(CALLER_ADDR0); - guest_enter_irqoff(); - lockdep_hardirqs_on(CALLER_ADDR0); - - /* L1D Flush includes CPU buffer clear to mitigate MDS */ - if (static_branch_unlikely(&vmx_l1d_should_flush)) - vmx_l1d_flush(vcpu); - else if (static_branch_unlikely(&mds_user_clear)) - mds_clear_cpu_buffers(); - - if (vcpu->arch.cr2 != read_cr2()) - write_cr2(vcpu->arch.cr2); - - vmx->fail = __vmx_vcpu_run(vmx, (unsigned long *)&vcpu->arch.regs, - vmx->loaded_vmcs->launched); - - vcpu->arch.cr2 = read_cr2(); - - /* - * VMEXIT disables interrupts (host state), but tracing and lockdep - * have them in state 'on' as recorded before entering guest mode. - * Same as enter_from_user_mode(). - * - * guest_exit_irqoff() restores host context and reinstates RCU if - * enabled and required. - * - * This needs to be done before the below as native_read_msr() - * contains a tracepoint and x86_spec_ctrl_restore_host() calls - * into world and some more. - */ - lockdep_hardirqs_off(CALLER_ADDR0); - guest_exit_irqoff(); - trace_hardirqs_off_finish(); + /* The actual VMENTER/EXIT is in the .noinstr.text section. */ + vmx_vcpu_enter_exit(vcpu, vmx); /* * We do not use IBRS in the kernel. If this vCPU has used the --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -379,7 +379,7 @@ int kvm_set_apic_base(struct kvm_vcpu *v } EXPORT_SYMBOL_GPL(kvm_set_apic_base); -asmlinkage __visible void kvm_spurious_fault(void) +asmlinkage __visible noinstr void kvm_spurious_fault(void) { /* Fault while not rebooting. We want the trace. */ BUG_ON(!kvm_rebooting);