From patchwork Wed Oct 20 12:04:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hikaru Nishida X-Patchwork-Id: 12572237 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E9047C433F5 for ; Wed, 20 Oct 2021 12:05:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CE8C5610FF for ; Wed, 20 Oct 2021 12:05:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230345AbhJTMHw (ORCPT ); Wed, 20 Oct 2021 08:07:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46360 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230281AbhJTMHn (ORCPT ); Wed, 20 Oct 2021 08:07:43 -0400 Received: from mail-pf1-x42b.google.com (mail-pf1-x42b.google.com [IPv6:2607:f8b0:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6BE4DC06161C for ; Wed, 20 Oct 2021 05:05:29 -0700 (PDT) Received: by mail-pf1-x42b.google.com with SMTP id m14so2767134pfc.9 for ; Wed, 20 Oct 2021 05:05:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=daEoZ9rYJqo1FQMfaT8aFEhZ3akBhgJvK+CaM2KA7dQ=; b=BuMErA/DuZ/0Gh1Uip5zDi4nhZy8bA5ENyyLMru7SulwHDqlPXRRu5eNimVwwXElC5 lq6qqAFosuH8kSRKMypo3mBPVPfFxgsCNvZm3K0A3h4isPdM1oj9JNELuPiXi0g495MS 1sTscOCX5xW9BG0Y+KVKAbxzfafNY9PQlv49k= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=daEoZ9rYJqo1FQMfaT8aFEhZ3akBhgJvK+CaM2KA7dQ=; b=2cfXjJJLB7HASAEiAsNkhkw31PwvRxM8jBu7KWdu7uLPF6gGYUW6KszvJKpisiozHL 9VPAdXGua+oqbUa2ANLXzwglpzvt6/5jnWwbM/RTdfXDpyivV8z31/D5BdWzV74x7bVK Hrs24G3sYBGAQWExdixqW4/zpwRHZkheLmphpgBRjmUe7LORYRzfIUu/yVBemqiGB8wc jP/rh/cFndynxaDY1Bub6Z4Uu+i3VD9VfUV+54hCK+Ls2CYLFILJJp9Z6yoDsu5aua6N s6gdoHtby4rjEIUKqgfzrkZJ2WzTNA/dn0Xh/oRjmhk7xhHnzdQem9nonC9GYAuUCoK2 f/cQ== X-Gm-Message-State: AOAM530z4kAljNVZ+YumCkq6lHJgys+mhzZZUwMYNTPPV8bg1+zNSX9p LBO+IwqqWX1JJTT4tRgHxup+sA== X-Google-Smtp-Source: ABdhPJx/Rvr3qcPZwTYCDZsWLdqpM8lN7/5ngKAA29ZJgCF1EtMVqY2etsqhKYaFyuZhxkUHOUFKeQ== X-Received: by 2002:a63:7888:: with SMTP id t130mr26794255pgc.279.1634731528796; Wed, 20 Oct 2021 05:05:28 -0700 (PDT) Received: from localhost ([2401:fa00:8f:203:e516:d575:e6f:a526]) by smtp.gmail.com with UTF8SMTPSA id d137sm2573453pfd.72.2021.10.20.05.05.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 20 Oct 2021 05:05:28 -0700 (PDT) From: Hikaru Nishida To: linux-kernel@vger.kernel.org, dme@dme.org, tglx@linutronix.de, mlevitsk@redhat.com, linux@roeck-us.net, pbonzini@redhat.com, vkuznets@redhat.com, maz@kernel.org, will@kernel.org Cc: suleiman@google.com, senozhatsky@google.com, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, Hikaru Nishida , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Dave Hansen , Geert Uytterhoeven , "H. Peter Anvin" , Ingo Molnar , Jim Mattson , Joerg Roedel , John Stultz , Juergen Gross , Kees Cook , Lai Jiangshan , Linus Walleij , Peter Zijlstra , Sean Christopherson , Stephen Boyd , Wanpeng Li , kvm@vger.kernel.org, x86@kernel.org Subject: [RFC PATCH v3 5/5] kvm/x86: virtual suspend time injection: Implement guest side Date: Wed, 20 Oct 2021 21:04:30 +0900 Message-Id: <20211020210348.RFC.v3.5.I99f7da15fd68fc098709ea4bcf74525e0883ea92@changeid> X-Mailer: git-send-email 2.33.0.1079.g6e70778dc9-goog In-Reply-To: <20211020120431.776494-1-hikalium@chromium.org> References: <20211020120431.776494-1-hikalium@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Add guest side implementation of KVM virtual suspend time injection. How it works from guest's view: - Guest will be paused without going through suspend/resume path in the guest kernel - Before resuming the execution of the guest's vcpus, host will adjust the hardware clock (and kvm_clock) to the time before the suspend. - By this action, guest's CLOCK_MONOTONIC behaves as expected (stops during the host's suspension.) - the guest will receive an IRQ from the guest that notifies about the suspend which was invisible to the guest. In the handler, the guest can adjust their CLOCK_BOOTTIME to reflect the suspension. - Now, CLOCK_BOOTTIME includes the time passed during the host's suspension. Signed-off-by: Hikaru Nishida --- Changes in v3: - Reused HYPERVISOR_CALLBACK_VECTOR IRQ instead of adding a new one. - Extracted arch-independent parts. arch/x86/Kconfig | 13 ++++++++ arch/x86/include/asm/idtentry.h | 2 +- arch/x86/include/asm/kvmclock.h | 9 ++++++ arch/x86/kernel/kvm.c | 14 ++++++--- arch/x86/kernel/kvmclock.c | 26 ++++++++++++++++ arch/x86/mm/fault.c | 2 +- include/linux/timekeeper_internal.h | 5 ++++ include/linux/timekeeping.h | 4 +++ kernel/time/timekeeping.c | 46 +++++++++++++++++++++++++++++ 9 files changed, 115 insertions(+), 6 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index d9830e7e1060..1d4a529d1577 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -824,6 +824,19 @@ config KVM_GUEST underlying device model, the host provides the guest with timing infrastructure such as time of day, and system time +config KVM_VIRT_SUSPEND_TIMING_GUEST + bool "Guest support for virtual suspend time injection" + depends on KVM_GUEST + default n + help + This option makes the host's suspension reflected on the guest's clocks. + In other words, guest's CLOCK_MONOTONIC will stop and + CLOCK_BOOTTIME keeps running during the host's suspension. + This feature will only be effective when both guest and host support + this feature. For the host side, see KVM_VIRT_SUSPEND_TIMING. + + If unsure, say N. + config ARCH_CPUIDLE_HALTPOLL def_bool n prompt "Disable host haltpoll when loading haltpoll driver" diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h index 1345088e9902..5e30f84ea07e 100644 --- a/arch/x86/include/asm/idtentry.h +++ b/arch/x86/include/asm/idtentry.h @@ -686,7 +686,7 @@ DECLARE_IDTENTRY_SYSVEC(HYPERVISOR_CALLBACK_VECTOR, sysvec_xen_hvm_callback); #endif #ifdef CONFIG_KVM_GUEST -DECLARE_IDTENTRY_SYSVEC(HYPERVISOR_CALLBACK_VECTOR, sysvec_kvm_asyncpf_interrupt); +DECLARE_IDTENTRY_SYSVEC(HYPERVISOR_CALLBACK_VECTOR, sysvec_kvm_hv_callback); #endif #undef X86_TRAP_OTHER diff --git a/arch/x86/include/asm/kvmclock.h b/arch/x86/include/asm/kvmclock.h index 9add14edc24d..2bf1a5c92319 100644 --- a/arch/x86/include/asm/kvmclock.h +++ b/arch/x86/include/asm/kvmclock.h @@ -20,4 +20,13 @@ static inline struct pvclock_vsyscall_time_info *this_cpu_hvclock(void) return this_cpu_read(hv_clock_per_cpu); } +#ifdef CONFIG_KVM_VIRT_SUSPEND_TIMING_GUEST +u64 kvm_get_suspend_time(void); +#else +static inline u64 kvm_get_suspend_time(void) +{ + return 0; +} +#endif + #endif /* _ASM_X86_KVM_CLOCK_H */ diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index b656456c3a94..3d84ef6d9df2 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -40,6 +40,7 @@ #include #include #include +#include DEFINE_STATIC_KEY_FALSE(kvm_async_pf_enabled); @@ -270,7 +271,7 @@ noinstr bool __kvm_handle_async_pf(struct pt_regs *regs, u32 token) return true; } -DEFINE_IDTENTRY_SYSVEC(sysvec_kvm_asyncpf_interrupt) +DEFINE_IDTENTRY_SYSVEC(sysvec_kvm_hv_callback) { struct pt_regs *old_regs = set_irq_regs(regs); u32 token; @@ -286,6 +287,8 @@ DEFINE_IDTENTRY_SYSVEC(sysvec_kvm_asyncpf_interrupt) wrmsrl(MSR_KVM_ASYNC_PF_ACK, 1); } + timekeeping_inject_virtual_suspend_time(kvm_get_suspend_time()); + set_irq_regs(old_regs); } @@ -710,10 +713,13 @@ static void __init kvm_guest_init(void) if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) apic_set_eoi_write(kvm_guest_apic_eoi_write); - if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_INT) && kvmapf) { + if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_INT) && kvmapf) static_branch_enable(&kvm_async_pf_enabled); - alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_kvm_asyncpf_interrupt); - } + + if ((kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_INT) && kvmapf) || + kvm_para_has_feature(KVM_FEATURE_HOST_SUSPEND_TIME)) + alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, + asm_sysvec_kvm_hv_callback); #ifdef CONFIG_SMP if (pv_tlb_flush_supported()) { diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index 73c74b961d0f..3e16d0ab79f3 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -16,11 +16,15 @@ #include #include #include +#include +#include #include #include #include #include +#include +#include static int kvmclock __initdata = 1; static int kvmclock_vsyscall __initdata = 1; @@ -48,6 +52,9 @@ early_param("no-kvmclock-vsyscall", parse_no_kvmclock_vsyscall); static struct pvclock_vsyscall_time_info hv_clock_boot[HVC_BOOT_ARRAY_SIZE] __bss_decrypted __aligned(PAGE_SIZE); +#ifdef CONFIG_KVM_VIRT_SUSPEND_TIMING_GUEST +static struct kvm_suspend_time suspend_time __bss_decrypted; +#endif static struct pvclock_wall_clock wall_clock __bss_decrypted; static struct pvclock_vsyscall_time_info *hvclock_mem; DEFINE_PER_CPU(struct pvclock_vsyscall_time_info *, hv_clock_per_cpu); @@ -281,6 +288,17 @@ static int kvmclock_setup_percpu(unsigned int cpu) return p ? 0 : -ENOMEM; } +#ifdef CONFIG_KVM_VIRT_SUSPEND_TIMING_GUEST +/** + * kvm_get_suspend_time - duration of host suspend. + * Return: Cumulative duration of host suspend in nanoseconds. + */ +u64 kvm_get_suspend_time(void) +{ + return suspend_time.suspend_time_ns; +} +#endif + void __init kvmclock_init(void) { u8 flags; @@ -295,6 +313,14 @@ void __init kvmclock_init(void) return; } +#ifdef CONFIG_KVM_VIRT_SUSPEND_TIMING_GUEST + if (kvm_para_has_feature(KVM_FEATURE_HOST_SUSPEND_TIME)) { + /* Register the suspend time structure */ + wrmsrl(MSR_KVM_HOST_SUSPEND_TIME, + slow_virt_to_phys(&suspend_time) | KVM_MSR_ENABLED); + } +#endif + if (cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "kvmclock:setup_percpu", kvmclock_setup_percpu, NULL) < 0) { return; diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 84a2c8c4af73..f36f49585d5d 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1509,7 +1509,7 @@ DEFINE_IDTENTRY_RAW_ERRORCODE(exc_page_fault) * memory is swapped out). Note, the corresponding "page ready" event * which is injected when the memory becomes available, is delivered via * an interrupt mechanism and not a #PF exception - * (see arch/x86/kernel/kvm.c: sysvec_kvm_asyncpf_interrupt()). + * (see arch/x86/kernel/kvm.c: sysvec_kvm_hv_callback()). * * We are relying on the interrupted context being sane (valid RSP, * relevant locks not held, etc.), which is fine as long as the diff --git a/include/linux/timekeeper_internal.h b/include/linux/timekeeper_internal.h index 84ff2844df2a..0d5b29122d40 100644 --- a/include/linux/timekeeper_internal.h +++ b/include/linux/timekeeper_internal.h @@ -68,6 +68,8 @@ struct tk_read_base { * shifted nano seconds. * @ntp_error_shift: Shift conversion between clock shifted nano seconds and * ntp shifted nano seconds. + * @kvm_suspend_time: The cumulative duration of suspend injected through KVM + * in nano seconds. * @last_warning: Warning ratelimiter (DEBUG_TIMEKEEPING) * @underflow_seen: Underflow warning flag (DEBUG_TIMEKEEPING) * @overflow_seen: Overflow warning flag (DEBUG_TIMEKEEPING) @@ -124,6 +126,9 @@ struct timekeeper { u32 ntp_err_mult; /* Flag used to avoid updating NTP twice with same second */ u32 skip_second_overflow; +#ifdef CONFIG_KVM_VIRT_SUSPEND_TIMING_GUEST + u64 kvm_suspend_time; +#endif #ifdef CONFIG_DEBUG_TIMEKEEPING long last_warning; /* diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h index f7be69c81dab..a2228300c3f9 100644 --- a/include/linux/timekeeping.h +++ b/include/linux/timekeeping.h @@ -310,4 +310,8 @@ void read_persistent_wall_and_boot_offset(struct timespec64 *wall_clock, extern int update_persistent_clock64(struct timespec64 now); #endif +#ifdef CONFIG_KVM_VIRT_SUSPEND_TIMING_GUEST +void timekeeping_inject_virtual_suspend_time(u64 total_duration_ns); +#endif + #endif diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index e77580d9f8c1..5f474cde0bae 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -2133,6 +2133,52 @@ static u64 logarithmic_accumulation(struct timekeeper *tk, u64 offset, return offset; } +#ifdef CONFIG_KVM_VIRT_SUSPEND_TIMING_GUEST +/** + * timekeeping_inject_virtual_suspend_time - Inject virtual suspend time + * when requested by the kvm host. + * @total_duration_ns: Total suspend time to be injected in nanoseconds. + */ +void timekeeping_inject_virtual_suspend_time(u64 total_duration_ns) +{ + struct timekeeper *tk = &tk_core.timekeeper; + unsigned long flags; + + raw_spin_lock_irqsave(&timekeeper_lock, flags); + if (total_duration_ns > tk->kvm_suspend_time) { + /* + * Do injection only if the time is not injected yet. + * total_duration_ns and tk->kvm_suspend_time values are + * cumulative, so the delta between them will be an amount + * of adjustments. For example, if the host suspends 2 times + * during the guest is running and each suspend is 5 seconds, + * total_duration_ns will be 5 seconds at the first injection + * and tk->kvm_suspend_time was initialized to zero so the + * adjustment injected here will be 5 - 0 = 5 seconds and + * tk->kvm_suspend_time will be updated to 5 seconds. + * On the second injection after the second resume, + * total_duration_ns will be 10 seconds and + * tk->kvm_suspend_time will be 5 seconds so 10 - 5 = 5 seconds + * of the suspend time will be injected again. + */ + struct timespec64 delta = + ns_to_timespec64(total_duration_ns - + tk->kvm_suspend_time); + tk->kvm_suspend_time = total_duration_ns; + + write_seqcount_begin(&tk_core.seq); + timekeeping_forward_now(tk); + __timekeeping_inject_sleeptime(tk, &delta); + timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET); + write_seqcount_end(&tk_core.seq); + + /* signal hrtimers about time change */ + clock_was_set_delayed(); + } + raw_spin_unlock_irqrestore(&timekeeper_lock, flags); +} +#endif + /* * timekeeping_advance - Updates the timekeeper to the current time and * current NTP tick length