From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 6BB401CF5FB; Wed, 2 Oct 2024 13:45:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727876709; cv=none; b=gPxV6DGFKbUgej9eN2sb4IXDfr8pYlWFkI0cATOD+ED95CpwXghXroK2lC3vFeTdKLN/8p36tlXms0zPdiyUlm3sDgSoSAJtZ36iusGAIFQLLYqdvEOW3JcXAmVtjlsy4c68OuqqppVNNTVbgQQTw0hmsfgDgx+cjkvFgX36RK8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727876709; c=relaxed/simple; bh=YfLyGvrlBq2/PVFVzAlsjgryK6Cpkthn3mNKnzU/i4I=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=s+ydnnNbpxO9U4f8aPWKeLRfxzL5GDpEOySL7y/CIe1WyipRSehq35bcs6TPQ6dcwvB1WQDJyXyeAA4N4MuPya4q1og4tkwTWGQqOP+CX0452SQwLdC1vtj2DVjm7lHzTHoopigBl23QgqEJMMmYIZpYR+YlMDVAWHTqUTbHL2Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Hj0mW8M0; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Hj0mW8M0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E8D10C4CEC5; Wed, 2 Oct 2024 13:45:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1727876709; bh=YfLyGvrlBq2/PVFVzAlsjgryK6Cpkthn3mNKnzU/i4I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Hj0mW8M0kMR6KrKXXrSxMXqFM9EZiM0EUA7bmAZeUSAvQc5V7qUgUNFdm2jCY9pKe sMcxUoizEo991SWTxtl8XriQf7aXlLyQgDSU1XOYtlH7sj7KMsnEbLXIeUZvHv2cUc 9/fa9TpAxbB7r7K+D8sseHOhPMN+YQrv6jnUOyL4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Maxim Levitsky , Suravee Suthikulpanit , Sean Christopherson Subject: [PATCH 6.11 537/695] KVM: x86: Re-split x2APIC ICR into ICR+ICR2 for AMD (x2AVIC) Date: Wed, 2 Oct 2024 14:58:55 +0200 Message-ID: <20241002125843.934719118@linuxfoundation.org> X-Mailer: git-send-email 2.46.2 In-Reply-To: <20241002125822.467776898@linuxfoundation.org> References: <20241002125822.467776898@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sean Christopherson commit 73b42dc69be8564d4951a14d00f827929fe5ef79 upstream. Re-introduce the "split" x2APIC ICR storage that KVM used prior to Intel's IPI virtualization support, but only for AMD. While not stated anywhere in the APM, despite stating the ICR is a single 64-bit register, AMD CPUs store the 64-bit ICR as two separate 32-bit values in ICR and ICR2. When IPI virtualization (IPIv on Intel, all AVIC flavors on AMD) is enabled, KVM needs to match CPU behavior as some ICR ICR writes will be handled by the CPU, not by KVM. Add a kvm_x86_ops knob to control the underlying format used by the CPU to store the x2APIC ICR, and tune it to AMD vs. Intel regardless of whether or not x2AVIC is enabled. If KVM is handling all ICR writes, the storage format for x2APIC mode doesn't matter, and having the behavior follow AMD versus Intel will provide better test coverage and ease debugging. Fixes: 4d1d7942e36a ("KVM: SVM: Introduce logic to (de)activate x2AVIC mode") Cc: stable@vger.kernel.org Cc: Maxim Levitsky Cc: Suravee Suthikulpanit Link: https://lore.kernel.org/r/20240719235107.3023592-4-seanjc@google.com Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/kvm_host.h | 2 + arch/x86/kvm/lapic.c | 42 ++++++++++++++++++++++++++++------------ arch/x86/kvm/svm/svm.c | 2 + arch/x86/kvm/vmx/main.c | 2 + 4 files changed, 36 insertions(+), 12 deletions(-) --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1727,6 +1727,8 @@ struct kvm_x86_ops { void (*enable_nmi_window)(struct kvm_vcpu *vcpu); void (*enable_irq_window)(struct kvm_vcpu *vcpu); void (*update_cr8_intercept)(struct kvm_vcpu *vcpu, int tpr, int irr); + + const bool x2apic_icr_is_split; const unsigned long required_apicv_inhibits; bool allow_apicv_in_x2apic_without_x2apic_virtualization; void (*refresh_apicv_exec_ctrl)(struct kvm_vcpu *vcpu); --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -2471,11 +2471,25 @@ int kvm_x2apic_icr_write(struct kvm_lapi data &= ~APIC_ICR_BUSY; kvm_apic_send_ipi(apic, (u32)data, (u32)(data >> 32)); - kvm_lapic_set_reg64(apic, APIC_ICR, data); + if (kvm_x86_ops.x2apic_icr_is_split) { + kvm_lapic_set_reg(apic, APIC_ICR, data); + kvm_lapic_set_reg(apic, APIC_ICR2, data >> 32); + } else { + kvm_lapic_set_reg64(apic, APIC_ICR, data); + } trace_kvm_apic_write(APIC_ICR, data); return 0; } +static u64 kvm_x2apic_icr_read(struct kvm_lapic *apic) +{ + if (kvm_x86_ops.x2apic_icr_is_split) + return (u64)kvm_lapic_get_reg(apic, APIC_ICR) | + (u64)kvm_lapic_get_reg(apic, APIC_ICR2) << 32; + + return kvm_lapic_get_reg64(apic, APIC_ICR); +} + /* emulate APIC access in a trap manner */ void kvm_apic_write_nodecode(struct kvm_vcpu *vcpu, u32 offset) { @@ -2493,7 +2507,7 @@ void kvm_apic_write_nodecode(struct kvm_ * maybe-unecessary write, and both are in the noise anyways. */ if (apic_x2apic_mode(apic) && offset == APIC_ICR) - WARN_ON_ONCE(kvm_x2apic_icr_write(apic, kvm_lapic_get_reg64(apic, APIC_ICR))); + WARN_ON_ONCE(kvm_x2apic_icr_write(apic, kvm_x2apic_icr_read(apic))); else kvm_lapic_reg_write(apic, offset, kvm_lapic_get_reg(apic, offset)); } @@ -3013,18 +3027,22 @@ static int kvm_apic_state_fixup(struct k /* * In x2APIC mode, the LDR is fixed and based on the id. And - * ICR is internally a single 64-bit register, but needs to be - * split to ICR+ICR2 in userspace for backwards compatibility. + * if the ICR is _not_ split, ICR is internally a single 64-bit + * register, but needs to be split to ICR+ICR2 in userspace for + * backwards compatibility. */ - if (set) { + if (set) *ldr = kvm_apic_calc_x2apic_ldr(x2apic_id); - icr = __kvm_lapic_get_reg(s->regs, APIC_ICR) | - (u64)__kvm_lapic_get_reg(s->regs, APIC_ICR2) << 32; - __kvm_lapic_set_reg64(s->regs, APIC_ICR, icr); - } else { - icr = __kvm_lapic_get_reg64(s->regs, APIC_ICR); - __kvm_lapic_set_reg(s->regs, APIC_ICR2, icr >> 32); + if (!kvm_x86_ops.x2apic_icr_is_split) { + if (set) { + icr = __kvm_lapic_get_reg(s->regs, APIC_ICR) | + (u64)__kvm_lapic_get_reg(s->regs, APIC_ICR2) << 32; + __kvm_lapic_set_reg64(s->regs, APIC_ICR, icr); + } else { + icr = __kvm_lapic_get_reg64(s->regs, APIC_ICR); + __kvm_lapic_set_reg(s->regs, APIC_ICR2, icr >> 32); + } } } @@ -3222,7 +3240,7 @@ static int kvm_lapic_msr_read(struct kvm u32 low; if (reg == APIC_ICR) { - *data = kvm_lapic_get_reg64(apic, APIC_ICR); + *data = kvm_x2apic_icr_read(apic); return 0; } --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -5062,6 +5062,8 @@ static struct kvm_x86_ops svm_x86_ops __ .enable_nmi_window = svm_enable_nmi_window, .enable_irq_window = svm_enable_irq_window, .update_cr8_intercept = svm_update_cr8_intercept, + + .x2apic_icr_is_split = true, .set_virtual_apic_mode = avic_refresh_virtual_apic_mode, .refresh_apicv_exec_ctrl = avic_refresh_apicv_exec_ctrl, .apicv_post_state_restore = avic_apicv_post_state_restore, --- a/arch/x86/kvm/vmx/main.c +++ b/arch/x86/kvm/vmx/main.c @@ -89,6 +89,8 @@ struct kvm_x86_ops vt_x86_ops __initdata .enable_nmi_window = vmx_enable_nmi_window, .enable_irq_window = vmx_enable_irq_window, .update_cr8_intercept = vmx_update_cr8_intercept, + + .x2apic_icr_is_split = false, .set_virtual_apic_mode = vmx_set_virtual_apic_mode, .set_apic_access_page_addr = vmx_set_apic_access_page_addr, .refresh_apicv_exec_ctrl = vmx_refresh_apicv_exec_ctrl,