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 47C47C0219B for ; Tue, 11 Feb 2025 13:05:42 +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:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Y6KhyRBobv8kAjzcOlt3WqozMXYuMwC8hKPDJMfq4hQ=; b=SVtQ15IoqdB4IpOTcBJz8rroW7 zUmldM0RcpPiIQIorgsC3VS0vWgjMXwGhDid3o58+6yZqBm8UkBENzP5crrxPvcKlgr8s3Dtg8ay1 FYoarEOT1HPjIuQXe/I2RPbxl5yRx6mlC0pJ8csqWfsH7TT6kioMGg4VkV6xQK/v3WjeZayLcM+UI qF4sgcPziWni7/vu7jfI8XBolXVPjOfWTY4++ceRupTqxR6lda0qBoOQ+nj1qSgl5TB5nz8ZG9yZd ZHkfHFKhnsvn3ov4HAfeKWANUxK/uGkwTcqDb452/pec1FylFjMTa0AhE/8jNRBw6LldBuYVWdm59 BR5jsVlA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1thpxC-00000003slA-3MLT; Tue, 11 Feb 2025 13:05:30 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1thpNA-00000003lm7-26gs for linux-arm-kernel@lists.infradead.org; Tue, 11 Feb 2025 12:28:17 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2B4B11424; Tue, 11 Feb 2025 04:28:36 -0800 (PST) Received: from J2N7QTR9R3 (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4EB3A3F6A8; Tue, 11 Feb 2025 04:28:13 -0800 (PST) Date: Tue, 11 Feb 2025 12:28:10 +0000 From: Mark Rutland To: Marc Zyngier Cc: kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Joey Gouly , Suzuki K Poulose , Oliver Upton , Zenghui Yu , Fuad Tabba Subject: Re: [PATCH 03/18] KVM: arm64: Handle trapping of FEAT_LS64* instructions Message-ID: References: <20250210184150.2145093-1-maz@kernel.org> <20250210184150.2145093-4-maz@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250210184150.2145093-4-maz@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250211_042816_633799_7AF1EA18 X-CRM114-Status: GOOD ( 21.50 ) 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 On Mon, Feb 10, 2025 at 06:41:34PM +0000, Marc Zyngier wrote: > We generally don't expect FEAT_LS64* instructions to trap, unless > they are trapped by a guest hypervisor. > > Otherwise, this is just the guest playing tricks on us by using > an instruction that isn't advertised, which we handle with a well > deserved UNDEF. > > Signed-off-by: Marc Zyngier > --- > arch/arm64/kvm/handle_exit.c | 64 ++++++++++++++++++++++++++++++++++++ > 1 file changed, 64 insertions(+) > > diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c > index 512d152233ff2..4f8354bf7dc5f 100644 > --- a/arch/arm64/kvm/handle_exit.c > +++ b/arch/arm64/kvm/handle_exit.c > @@ -294,6 +294,69 @@ static int handle_svc(struct kvm_vcpu *vcpu) > return 1; > } > > +static int handle_ls64b(struct kvm_vcpu *vcpu) Structurally this looks good. As noted on patch 2, I think that naming-wise this should be more general, e.g. handle_other_insn(). Mark. > +{ > + struct kvm *kvm = vcpu->kvm; > + u64 esr = kvm_vcpu_get_esr(vcpu); > + u64 iss = ESR_ELx_ISS(esr); > + bool allowed; > + > + switch (iss) { > + case ESR_ELx_ISS_ST64BV: > + allowed = kvm_has_feat(kvm, ID_AA64ISAR1_EL1, LS64, LS64_V); > + break; > + case ESR_ELx_ISS_ST64BV0: > + allowed = kvm_has_feat(kvm, ID_AA64ISAR1_EL1, LS64, LS64_ACCDATA); > + break; > + case ESR_ELx_ISS_LDST64B: > + allowed = kvm_has_feat(kvm, ID_AA64ISAR1_EL1, LS64, LS64); > + break; > + default: > + /* Clearly, we're missing something. */ > + goto unknown_trap; > + } > + > + if (!allowed) > + goto undef; > + > + if (vcpu_has_nv(vcpu) && !is_hyp_ctxt(vcpu)) { > + u64 hcrx = __vcpu_sys_reg(vcpu, HCRX_EL2); > + bool fwd; > + > + switch (iss) { > + case ESR_ELx_ISS_ST64BV: > + fwd = !(hcrx & HCRX_EL2_EnASR); > + break; > + case ESR_ELx_ISS_ST64BV0: > + fwd = !(hcrx & HCRX_EL2_EnAS0); > + break; > + case ESR_ELx_ISS_LDST64B: > + fwd = !(hcrx & HCRX_EL2_EnALS); > + break; > + default: > + /* We don't expect to be here */ > + fwd = false; > + } > + > + if (fwd) { > + kvm_inject_nested_sync(vcpu, esr); > + return 1; > + } > + } > + > +unknown_trap: > + /* > + * If we land here, something must be very wrong, because we > + * have no idea why we trapped at all. Warn and undef as a > + * fallback. > + */ > + WARN_ON(1); > + > +undef: > + kvm_inject_undefined(vcpu); > + return 1; > +} > + > static exit_handle_fn arm_exit_handlers[] = { > [0 ... ESR_ELx_EC_MAX] = kvm_handle_unknown_ec, > [ESR_ELx_EC_WFx] = kvm_handle_wfx, > @@ -303,6 +366,7 @@ static exit_handle_fn arm_exit_handlers[] = { > [ESR_ELx_EC_CP14_LS] = kvm_handle_cp14_load_store, > [ESR_ELx_EC_CP10_ID] = kvm_handle_cp10_id, > [ESR_ELx_EC_CP14_64] = kvm_handle_cp14_64, > + [ESR_ELx_EC_LS64B] = handle_ls64b, > [ESR_ELx_EC_HVC32] = handle_hvc, > [ESR_ELx_EC_SMC32] = handle_smc, > [ESR_ELx_EC_HVC64] = handle_hvc, > -- > 2.39.2 >