From patchwork Tue Feb 27 11:49:20 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Woodhouse X-Patchwork-Id: 13573725 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E8654146009 for ; Tue, 27 Feb 2024 12:19:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709036366; cv=none; b=QNm7nx9TqU4UrojM11Bf+HRPNjNfzDt18JK8G3yIm2YHHQdc5ZkfoYic9kaOFZKHjo57d0od0UDMZaJ1c/v8bynv9AVcAIFkYjt1kUkjyPmYUzSGTgcD/3OYJ7HxO+xMdrS0+QIJMKCKhMS7k0DbzzcbqDUQzH6rvYvEZcRyqOM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709036366; c=relaxed/simple; bh=d8vgNyQwZfsDXdkfeL5PhgxhbR732Ns+eP3wEDj36ck=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Ivn5WBWT31kwKztDcf6NaARZK8LVytDMRVa8TpDskdOhBQG3BKG1z8+2qxjc4kc6zwi3LJQyi9RCfoCdjNBCpFMHSxwlV1VZFaBTfqFXifh0o63jj4Vj7jyAztcxqWFzBqntWJO96JqeQFVnwdu0sSrD6VzF6+9ClUo9em7N1JE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=casper.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=seMRokYK; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=casper.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="seMRokYK" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Sender:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description; bh=mZmUrqTSZafu4Ig0+vbHfabSb5U88VLiQudL87QgNhI=; b=seMRokYKlWuSuTxAYXnXaX4ord bJIhQtPebbnvQJLTv697hWa73T1NfZ1FVQmLp3Ha2MOTY/a0wSpjgYYreSCkltbHaKxQsqSsQC/CY wqFQfEx+PnUIe7x8MZmzhcZWQuh7zqqut/yiuoNuUrWHRCUVrzDI7aOwMhpDzVgbp/5UT37V56Jai +6Kv/l6QVNftqmpnVfx0p0ITu/JRwf0PGnjwNM+p6X0dDx/Dt8s+nINUNlyCwyQ9m/S1sx0coM9DD OAKNJq8yPfHqSuu6zGm69fH6W+rKJNcwfK7xkzxDJ6w4PR19dhzyPvDlclu5ObMxaBOw2Qi+XtNWO xuWSwQxg==; Received: from [2001:8b0:10b:1::ebe] (helo=i7.infradead.org) by casper.infradead.org with esmtpsa (Exim 4.97.1 #2 (Red Hat Linux)) id 1rew4p-00000002JfQ-3Fwp; Tue, 27 Feb 2024 11:56:52 +0000 Received: from dwoodhou by i7.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1rew4o-000000000wd-0Hoh; Tue, 27 Feb 2024 11:56:50 +0000 From: David Woodhouse To: kvm@vger.kernel.org Cc: Sean Christopherson , Paul Durrant , Paolo Bonzini , Michal Luczaj , Paul Durrant , David Woodhouse , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , David Woodhouse , x86@kernel.org Subject: [PATCH v2 6/8] KVM: x86/xen: split up kvm_xen_set_evtchn_fast() Date: Tue, 27 Feb 2024 11:49:20 +0000 Message-ID: <20240227115648.3104-7-dwmw2@infradead.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240227115648.3104-1-dwmw2@infradead.org> References: <20240227115648.3104-1-dwmw2@infradead.org> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Sender: David Woodhouse X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html From: Paul Durrant The implementation of kvm_xen_set_evtchn_fast() is a rather lengthy piece of code that performs two operations: updating of the shared_info evtchn_pending mask, and updating of the vcpu_info evtchn_pending_sel mask. Introduce a separate function to perform each of those operations and re-work kvm_xen_set_evtchn_fast() to use them. No functional change intended. Signed-off-by: Paul Durrant Reviewed-by: David Woodhouse --- Cc: Sean Christopherson Cc: Paolo Bonzini Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: "H. Peter Anvin" Cc: David Woodhouse Cc: x86@kernel.org --- arch/x86/kvm/xen.c | 173 ++++++++++++++++++++++++++------------------- 1 file changed, 99 insertions(+), 74 deletions(-) diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c index e87b36590809..c16b6d394d55 100644 --- a/arch/x86/kvm/xen.c +++ b/arch/x86/kvm/xen.c @@ -1728,112 +1728,137 @@ static void kvm_xen_check_poller(struct kvm_vcpu *vcpu, int port) } } -/* - * The return value from this function is propagated to kvm_set_irq() API, - * so it returns: - * < 0 Interrupt was ignored (masked or not delivered for other reasons) - * = 0 Interrupt was coalesced (previous irq is still pending) - * > 0 Number of CPUs interrupt was delivered to - * - * It is also called directly from kvm_arch_set_irq_inatomic(), where the - * only check on its return value is a comparison with -EWOULDBLOCK'. - */ -int kvm_xen_set_evtchn_fast(struct kvm_xen_evtchn *xe, struct kvm *kvm) +static int set_shinfo_evtchn_pending(struct kvm_vcpu *vcpu, u32 port) { + struct kvm *kvm = vcpu->kvm; struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache; - struct kvm_vcpu *vcpu; unsigned long *pending_bits, *mask_bits; unsigned long flags; - int port_word_bit; - bool kick_vcpu = false; - int vcpu_idx, idx, rc; - - vcpu_idx = READ_ONCE(xe->vcpu_idx); - if (vcpu_idx >= 0) - vcpu = kvm_get_vcpu(kvm, vcpu_idx); - else { - vcpu = kvm_get_vcpu_by_id(kvm, xe->vcpu_id); - if (!vcpu) - return -EINVAL; - WRITE_ONCE(xe->vcpu_idx, vcpu->vcpu_idx); - } - - if (xe->port >= max_evtchn_port(kvm)) - return -EINVAL; - - rc = -EWOULDBLOCK; - - idx = srcu_read_lock(&kvm->srcu); + int rc = -EWOULDBLOCK; read_lock_irqsave(&gpc->lock, flags); if (!kvm_gpc_check(gpc, PAGE_SIZE)) - goto out_rcu; + goto out; if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) { struct shared_info *shinfo = gpc->khva; + pending_bits = (unsigned long *)&shinfo->evtchn_pending; mask_bits = (unsigned long *)&shinfo->evtchn_mask; - port_word_bit = xe->port / 64; } else { struct compat_shared_info *shinfo = gpc->khva; + pending_bits = (unsigned long *)&shinfo->evtchn_pending; mask_bits = (unsigned long *)&shinfo->evtchn_mask; - port_word_bit = xe->port / 32; } - /* - * If this port wasn't already set, and if it isn't masked, then - * we try to set the corresponding bit in the in-kernel shadow of - * evtchn_pending_sel for the target vCPU. And if *that* wasn't - * already set, then we kick the vCPU in question to write to the - * *real* evtchn_pending_sel in its own guest vcpu_info struct. - */ - if (test_and_set_bit(xe->port, pending_bits)) { + if (test_and_set_bit(port, pending_bits)) { rc = 0; /* It was already raised */ - } else if (test_bit(xe->port, mask_bits)) { - rc = -ENOTCONN; /* Masked */ - kvm_xen_check_poller(vcpu, xe->port); + } else if (test_bit(port, mask_bits)) { + rc = -ENOTCONN; /* It is masked */ + kvm_xen_check_poller(vcpu, port); } else { - rc = 1; /* Delivered to the bitmap in shared_info. */ - /* Now switch to the vCPU's vcpu_info to set the index and pending_sel */ - read_unlock_irqrestore(&gpc->lock, flags); - gpc = &vcpu->arch.xen.vcpu_info_cache; + rc = 1; /* It is newly raised */ + } - read_lock_irqsave(&gpc->lock, flags); - if (!kvm_gpc_check(gpc, sizeof(struct vcpu_info))) { - /* - * Could not access the vcpu_info. Set the bit in-kernel - * and prod the vCPU to deliver it for itself. - */ + out: + read_unlock_irqrestore(&gpc->lock, flags); + return rc; +} + +static bool set_vcpu_info_evtchn_pending(struct kvm_vcpu *vcpu, u32 port) +{ + struct kvm *kvm = vcpu->kvm; + struct gfn_to_pfn_cache *gpc = &vcpu->arch.xen.vcpu_info_cache; + unsigned long flags; + bool kick_vcpu = false; + + read_lock_irqsave(&gpc->lock, flags); + + /* + * Try to deliver the event directly to the vcpu_info. If successful and + * the guest is using upcall_vector delivery, send the MSI. + * If the pfncache is invalid, set the shadow. In this case, or if the + * guest is using another form of event delivery, the vCPU must be + * kicked to complete the delivery. + */ + if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) { + struct vcpu_info *vcpu_info = gpc->khva; + int port_word_bit = port / 64; + + if (!kvm_gpc_check(gpc, sizeof(*vcpu_info))) { if (!test_and_set_bit(port_word_bit, &vcpu->arch.xen.evtchn_pending_sel)) kick_vcpu = true; - goto out_rcu; + goto out; } - if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) { - struct vcpu_info *vcpu_info = gpc->khva; - if (!test_and_set_bit(port_word_bit, &vcpu_info->evtchn_pending_sel)) { - WRITE_ONCE(vcpu_info->evtchn_upcall_pending, 1); - kick_vcpu = true; - } - } else { - struct compat_vcpu_info *vcpu_info = gpc->khva; - if (!test_and_set_bit(port_word_bit, - (unsigned long *)&vcpu_info->evtchn_pending_sel)) { - WRITE_ONCE(vcpu_info->evtchn_upcall_pending, 1); + if (!test_and_set_bit(port_word_bit, &vcpu_info->evtchn_pending_sel)) { + WRITE_ONCE(vcpu_info->evtchn_upcall_pending, 1); + kick_vcpu = true; + } + } else { + struct compat_vcpu_info *vcpu_info = gpc->khva; + int port_word_bit = port / 32; + + if (!kvm_gpc_check(gpc, sizeof(*vcpu_info))) { + if (!test_and_set_bit(port_word_bit, &vcpu->arch.xen.evtchn_pending_sel)) kick_vcpu = true; - } + goto out; } - /* For the per-vCPU lapic vector, deliver it as MSI. */ - if (kick_vcpu && vcpu->arch.xen.upcall_vector) { - kvm_xen_inject_vcpu_vector(vcpu); - kick_vcpu = false; + if (!test_and_set_bit(port_word_bit, + (unsigned long *)&vcpu_info->evtchn_pending_sel)) { + WRITE_ONCE(vcpu_info->evtchn_upcall_pending, 1); + kick_vcpu = true; } } - out_rcu: + if (kick_vcpu && vcpu->arch.xen.upcall_vector) { + kvm_xen_inject_vcpu_vector(vcpu); + kick_vcpu = false; + } + + out: read_unlock_irqrestore(&gpc->lock, flags); + return kick_vcpu; +} + +/* + * The return value from this function is propagated to kvm_set_irq() API, + * so it returns: + * < 0 Interrupt was ignored (masked or not delivered for other reasons) + * = 0 Interrupt was coalesced (previous irq is still pending) + * > 0 Number of CPUs interrupt was delivered to + * + * It is also called directly from kvm_arch_set_irq_inatomic(), where the + * only check on its return value is a comparison with -EWOULDBLOCK + * (which may be returned by set_shinfo_evtchn_pending()). + */ +int kvm_xen_set_evtchn_fast(struct kvm_xen_evtchn *xe, struct kvm *kvm) +{ + struct kvm_vcpu *vcpu; + bool kick_vcpu = false; + int vcpu_idx, idx, rc; + + vcpu_idx = READ_ONCE(xe->vcpu_idx); + if (vcpu_idx >= 0) + vcpu = kvm_get_vcpu(kvm, vcpu_idx); + else { + vcpu = kvm_get_vcpu_by_id(kvm, xe->vcpu_id); + if (!vcpu) + return -EINVAL; + WRITE_ONCE(xe->vcpu_idx, vcpu->vcpu_idx); + } + + if (xe->port >= max_evtchn_port(kvm)) + return -EINVAL; + + idx = srcu_read_lock(&kvm->srcu); + + rc = set_shinfo_evtchn_pending(vcpu, xe->port); + if (rc == 1) /* Delivered to the bitmap in shared_info */ + kick_vcpu = set_vcpu_info_evtchn_pending(vcpu, xe->port); + srcu_read_unlock(&kvm->srcu, idx); if (kick_vcpu) {