From mboxrd@z Thu Jan 1 00:00:00 1970 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 42C15C88E50 for ; Mon, 14 Sep 2026 11:34:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=OzlBv4LVliN5qNgFK6sUr7g7vdLbZroh00iI5mV/2X0=; b=eR7QyzrSg7vmkQbql44xJfhrvV o5nuuFs3PLkPAOONk0+/Wb+E6VddO/gGbDRupbwi4p0iepYDwWNo5sDVvAfGbblMfbk+hGplZk7rz 56X+3XjtD/DDlkUDJNfM3bbCEqcUAQn7lBjc0sSfm8nBltu9iAbX9/QHDeylou6gJssV+NpVdV4K/ WfZFBKS+p7tJqeYW4WhJ6EcttOLxWy0Vfn4eZ+Yti5nGXIkoHeyKPcdGkjRRQ7nQZ722rM0bMMzO7 5yX/1KGtr2mF2TR+QNLAChhcO5EZYAnz8FfoPQFPVPDgitDajL0rA57Z7Qzkt2U58NI86xivqpBq5 zYw3BV4w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x64xH-00000003G99-26qF; Mon, 14 Sep 2026 11:34:35 +0000 Received: from out-181.mta0.migadu.com ([2001:41d0:1004:224b::b5] helo=mta0.migadu.com) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x64xD-00000003G4F-2Jar for linux-arm-kernel@lists.infradead.org; Mon, 14 Sep 2026 11:34:32 +0000 X-Envelope-To: linux-arm-kernel@lists.infradead.org DKIM-Signature: a=rsa-sha256; bh=zOptQexS7lDj6c14lPjl14jvIGvWcUYj7AKr6A/egrA=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1789385669; v=1; x=1789990469; b=rblhoPtXxz492wXn2rmC6P3EigsQTY+kthB1QNO12W4cOY+i/ROSi0BXkW4l6TN0YVU3QxoB CwMAiUC1wJIbdqe3K5g8Spk52TJYIV1upa47vih3fQe6/XuApALX9QGn7C7n71dxXzpU8oP738J BwShJ+0BRmaKJ/bgcHf9dBE8= X-Envelope-To: linux-arm-kernel@lists.infradead.org Received: by smtp.migadu.com with ESMTPS id 4c887214f45f674d; Mon, 14 Sep 2026 11:34:29 +0000 X-Mizu-Trace-ID: 4c887214f45f674d X-Migadu-Flow: FLOW_OUT From: Fuad Tabba To: maz@kernel.org, oupton@kernel.org, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: catalin.marinas@arm.com, will@kernel.org, joey.gouly@arm.com, seiden@linux.ibm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, mark.rutland@arm.com, steven.price@arm.com, vdonnefort@google.com, qperret@google.com, tabba@google.com Subject: [PATCH v3 07/18] KVM: arm64: Add {flush,sync}_hyp_timer_state() primitives Date: Mon, 14 Sep 2026 12:33:27 +0100 Message-Id: <20260914113338.159227-8-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20260914113338.159227-1-fuad.tabba@linux.dev> References: <20260914113338.159227-1-fuad.tabba@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260914_043431_744777_A1CD3974 X-CRM114-Status: GOOD ( 13.25 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Marc Zyngier A protected guest's virtual timer is programmed from EL2's own copy of the state and read back there, so the host can't change the guest's deadline. cntvoff_el2 is zeroed, so the guest's virtual time is the physical time. The flush also preserves the guest's CNTV and CNTP CVAL/CTL across the host's full-context copy into the hyp vCPU, until the per-EC marshalling patch removes that copy. Signed-off-by: Marc Zyngier Co-developed-by: Fuad Tabba Signed-off-by: Fuad Tabba --- arch/arm64/kvm/hyp/nvhe/hyp-main.c | 39 ++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c index 229a4877d14f5..9cc8ef16897c1 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -154,6 +154,33 @@ static void sync_hyp_vgic_state(struct pkvm_hyp_vcpu *hyp_vcpu) host_cpu_if->vgic_lr[i] = hyp_cpu_if->vgic_lr[i]; } +static void flush_hyp_timer_state(struct pkvm_hyp_vcpu *hyp_vcpu) +{ + if (!pkvm_hyp_vcpu_is_protected(hyp_vcpu)) + return; + + /* A hyp vcpu has no offset, and sees vtime == ptime. */ + write_sysreg(0, cntvoff_el2); + write_sysreg_el0(__vcpu_sys_reg(&hyp_vcpu->vcpu, CNTV_CVAL_EL0), + SYS_CNTV_CVAL); + isb(); + write_sysreg_el0(__vcpu_sys_reg(&hyp_vcpu->vcpu, CNTV_CTL_EL0), + SYS_CNTV_CTL); +} + +static void sync_hyp_timer_state(struct pkvm_hyp_vcpu *hyp_vcpu) +{ + if (!pkvm_hyp_vcpu_is_protected(hyp_vcpu)) + return; + + /* + * Preserve the vtimer state so that it is always correct, + * even if the host tries to make a mess. + */ + __vcpu_assign_sys_reg(&hyp_vcpu->vcpu, CNTV_CVAL_EL0, read_sysreg_el0(SYS_CNTV_CVAL)); + __vcpu_assign_sys_reg(&hyp_vcpu->vcpu, CNTV_CTL_EL0, read_sysreg_el0(SYS_CNTV_CTL)); +} + static void __copy_vcpu_state(const struct kvm_vcpu *from_vcpu, struct kvm_vcpu *to_vcpu) { @@ -255,7 +282,17 @@ static void flush_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu) hyp_vcpu->vcpu.arch.mdcr_el2 = host_vcpu->arch.mdcr_el2; hyp_vcpu->vcpu.arch.iflags = host_vcpu->arch.iflags; } else { + u64 v_cval = hyp_vcpu->vcpu.arch.ctxt.sys_regs[CNTV_CVAL_EL0]; + u64 v_ctl = hyp_vcpu->vcpu.arch.ctxt.sys_regs[CNTV_CTL_EL0]; + u64 p_cval = hyp_vcpu->vcpu.arch.ctxt.sys_regs[CNTP_CVAL_EL0]; + u64 p_ctl = hyp_vcpu->vcpu.arch.ctxt.sys_regs[CNTP_CTL_EL0]; + hyp_vcpu->vcpu.arch.ctxt = host_vcpu->arch.ctxt; + + hyp_vcpu->vcpu.arch.ctxt.sys_regs[CNTV_CVAL_EL0] = v_cval; + hyp_vcpu->vcpu.arch.ctxt.sys_regs[CNTV_CTL_EL0] = v_ctl; + hyp_vcpu->vcpu.arch.ctxt.sys_regs[CNTP_CVAL_EL0] = p_cval; + hyp_vcpu->vcpu.arch.ctxt.sys_regs[CNTP_CTL_EL0] = p_ctl; } /* __hyp_running_vcpu must be NULL in a guest context. */ @@ -270,6 +307,7 @@ static void flush_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu) hyp_vcpu->vcpu.arch.vsesr_el2 = host_vcpu->arch.vsesr_el2; flush_hyp_vgic_state(hyp_vcpu); + flush_hyp_timer_state(hyp_vcpu); hyp_vcpu->vcpu.arch.pid = host_vcpu->arch.pid; @@ -318,6 +356,7 @@ static void sync_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu, u32 exit_reason) host_vcpu->arch.hcr_el2 |= hyp_vcpu->vcpu.arch.hcr_el2 & HCR_VSE; sync_hyp_vgic_state(hyp_vcpu); + sync_hyp_timer_state(hyp_vcpu); hyp_vcpu->exit_code = exit_reason; } -- 2.39.5