From patchwork Tue Aug 20 10:37:47 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 13769899 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 64E7018E77C; Tue, 20 Aug 2024 10:38:08 +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=1724150288; cv=none; b=PMjXe7U2tGXD0FNHpIgV0qV7jzWdm67AFTLrL/qWnPC1BVOBicEInQ4gLXf9Oa9NyTLQXqkyRTuScpkBV9YUNAC5ASju+l73wFT6pi8XdSwLHKjIugHFYBP2ZMVWOvfKtMtLIIBuRRRw6bSvSPSL9Qh8FAXdWtAOmP0IEJwoLW4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724150288; c=relaxed/simple; bh=aU4Ozt59GbaUbO3+PotNeMwxVTRMgu3/5LP0uRVy3Do=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=n+v0oxKQz8EwIhxm6UJtAVdft9fEfW/Rfzoqg9AVBslK8GbkvWAOs1wk15BuabeEVhIVZJks9PIqnjsK0FbwWwfhW3VoqtAktNuG7xCoBCjqEK1iwFQDV99E7g8dggnjM8f5DFkL+91/je4ECJZExyEAjc1oI+rxbgTtT6mRfao= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eyABIcgT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="eyABIcgT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C92D2C4AF1D; Tue, 20 Aug 2024 10:38:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1724150287; bh=aU4Ozt59GbaUbO3+PotNeMwxVTRMgu3/5LP0uRVy3Do=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eyABIcgT1aQd3O5WHw+/O1fh/pxaVRaMW45ZvyDWoFKmMD1prsBG5l48lH/nIM6qp c0ofGnUThD5tZvvto4wVh21qeV87123khrS6PxaZyXiIeEQVbZcdfa+zxv2s2ZMqE2 Mb05IYAlSTp5f8JCvB2n+OZraRNZZMv88sw4TgjcVwGg877ftjirhkLhqPhsLcfaho F760HlkNjCAER99crXtn13DqDX2JqmOT6W7uf1RocdJIsUO7et6d7yfco1TBBvrMtd 3HjulqvIp4O2f6gi8D4iBa6R7lqSz2wgLnuIfVi6lgiVvI8C+S8zjDNKBdKNbvIKL/ T/kVXJTtOXHuA== Received: from sofa.misterjones.org ([185.219.108.64] helo=valley-girl.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1sgMFZ-005Ea3-Rh; Tue, 20 Aug 2024 11:38:05 +0100 From: Marc Zyngier To: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org Cc: James Morse , Suzuki K Poulose , Oliver Upton , Zenghui Yu , Joey Gouly , Alexandru Elisei , Anshuman Khandual , Przemyslaw Gaj , Jintack Lim Subject: [PATCH v4 09/18] KVM: arm64: nv: Add basic emulation of AT S1E{0,1}{R,W} Date: Tue, 20 Aug 2024 11:37:47 +0100 Message-Id: <20240820103756.3545976-10-maz@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240820103756.3545976-1-maz@kernel.org> References: <20240820103756.3545976-1-maz@kernel.org> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, james.morse@arm.com, suzuki.poulose@arm.com, oliver.upton@linux.dev, yuzenghui@huawei.com, joey.gouly@arm.com, alexandru.elisei@arm.com, anshuman.khandual@arm.com, pgaj@cadence.com, jintack.lim@linaro.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Emulating AT instructions is one the tasks devolved to the host hypervisor when NV is on. Here, we take the basic approach of emulating AT S1E{0,1}{R,W} using the AT instructions themselves. While this mostly work, it doesn't *always* work: - S1 page tables can be swapped out - shadow S2 can be incomplete and not contain mappings for the S1 page tables We are not trying to handle these case here, and defer it to a later patch. Suitable comments indicate where we are in dire need of better handling. Co-developed-by: Jintack Lim Signed-off-by: Jintack Lim Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/kvm_asm.h | 1 + arch/arm64/kvm/Makefile | 2 +- arch/arm64/kvm/at.c | 140 +++++++++++++++++++++++++++++++ 3 files changed, 142 insertions(+), 1 deletion(-) create mode 100644 arch/arm64/kvm/at.c diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index 25f49f5fc4a6..9b6c9f4f4d88 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -236,6 +236,7 @@ extern void __kvm_tlb_flush_vmid(struct kvm_s2_mmu *mmu); extern int __kvm_tlbi_s1e2(struct kvm_s2_mmu *mmu, u64 va, u64 sys_encoding); extern void __kvm_timer_set_cntvoff(u64 cntvoff); +extern void __kvm_at_s1e01(struct kvm_vcpu *vcpu, u32 op, u64 vaddr); extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu); diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile index a6497228c5a8..8a3ae76b4da2 100644 --- a/arch/arm64/kvm/Makefile +++ b/arch/arm64/kvm/Makefile @@ -14,7 +14,7 @@ kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \ inject_fault.o va_layout.o handle_exit.o \ guest.o debug.o reset.o sys_regs.o stacktrace.o \ vgic-sys-reg-v3.o fpsimd.o pkvm.o \ - arch_timer.o trng.o vmid.o emulate-nested.o nested.o \ + arch_timer.o trng.o vmid.o emulate-nested.o nested.o at.o \ vgic/vgic.o vgic/vgic-init.o \ vgic/vgic-irqfd.o vgic/vgic-v2.o \ vgic/vgic-v3.o vgic/vgic-v4.o \ diff --git a/arch/arm64/kvm/at.c b/arch/arm64/kvm/at.c new file mode 100644 index 000000000000..da378ad834cd --- /dev/null +++ b/arch/arm64/kvm/at.c @@ -0,0 +1,140 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2017 - Linaro Ltd + * Author: Jintack Lim + */ + +#include +#include + +struct mmu_config { + u64 ttbr0; + u64 ttbr1; + u64 tcr; + u64 mair; + u64 sctlr; + u64 vttbr; + u64 vtcr; + u64 hcr; +}; + +static void __mmu_config_save(struct mmu_config *config) +{ + config->ttbr0 = read_sysreg_el1(SYS_TTBR0); + config->ttbr1 = read_sysreg_el1(SYS_TTBR1); + config->tcr = read_sysreg_el1(SYS_TCR); + config->mair = read_sysreg_el1(SYS_MAIR); + config->sctlr = read_sysreg_el1(SYS_SCTLR); + config->vttbr = read_sysreg(vttbr_el2); + config->vtcr = read_sysreg(vtcr_el2); + config->hcr = read_sysreg(hcr_el2); +} + +static void __mmu_config_restore(struct mmu_config *config) +{ + write_sysreg(config->hcr, hcr_el2); + + /* + * ARM errata 1165522 and 1530923 require TGE to be 1 before + * we update the guest state. + */ + asm(ALTERNATIVE("nop", "isb", ARM64_WORKAROUND_SPECULATIVE_AT)); + + write_sysreg_el1(config->ttbr0, SYS_TTBR0); + write_sysreg_el1(config->ttbr1, SYS_TTBR1); + write_sysreg_el1(config->tcr, SYS_TCR); + write_sysreg_el1(config->mair, SYS_MAIR); + write_sysreg_el1(config->sctlr, SYS_SCTLR); + write_sysreg(config->vttbr, vttbr_el2); + write_sysreg(config->vtcr, vtcr_el2); +} + +/* + * Return the PAR_EL1 value as the result of a valid translation. + * + * If the translation is unsuccessful, the value may only contain + * PAR_EL1.F, and cannot be taken at face value. It isn't an + * indication of the translation having failed, only that the fast + * path did not succeed, *unless* it indicates a S1 permission fault. + */ +static u64 __kvm_at_s1e01_fast(struct kvm_vcpu *vcpu, u32 op, u64 vaddr) +{ + struct mmu_config config; + struct kvm_s2_mmu *mmu; + bool fail; + u64 par; + + par = SYS_PAR_EL1_F; + + /* + * We've trapped, so everything is live on the CPU. As we will + * be switching contexts behind everybody's back, disable + * interrupts while holding the mmu lock. + */ + guard(write_lock_irqsave)(&vcpu->kvm->mmu_lock); + + /* + * If HCR_EL2.{E2H,TGE} == {1,1}, the MMU context is already + * the right one (as we trapped from vEL2). If not, save the + * full MMU context. + */ + if (vcpu_el2_e2h_is_set(vcpu) && vcpu_el2_tge_is_set(vcpu)) + goto skip_mmu_switch; + + /* + * Obtaining the S2 MMU for a L2 is horribly racy, and we may not + * find it (recycled by another vcpu, for example). When this + * happens, admit defeat immediately and use the SW (slow) path. + */ + mmu = lookup_s2_mmu(vcpu); + if (!mmu) + return par; + + __mmu_config_save(&config); + + write_sysreg_el1(vcpu_read_sys_reg(vcpu, TTBR0_EL1), SYS_TTBR0); + write_sysreg_el1(vcpu_read_sys_reg(vcpu, TTBR1_EL1), SYS_TTBR1); + write_sysreg_el1(vcpu_read_sys_reg(vcpu, TCR_EL1), SYS_TCR); + write_sysreg_el1(vcpu_read_sys_reg(vcpu, MAIR_EL1), SYS_MAIR); + write_sysreg_el1(vcpu_read_sys_reg(vcpu, SCTLR_EL1), SYS_SCTLR); + __load_stage2(mmu, mmu->arch); + +skip_mmu_switch: + /* Clear TGE, enable S2 translation, we're rolling */ + write_sysreg((config.hcr & ~HCR_TGE) | HCR_VM, hcr_el2); + isb(); + + switch (op) { + case OP_AT_S1E1R: + fail = __kvm_at(OP_AT_S1E1R, vaddr); + break; + case OP_AT_S1E1W: + fail = __kvm_at(OP_AT_S1E1W, vaddr); + break; + case OP_AT_S1E0R: + fail = __kvm_at(OP_AT_S1E0R, vaddr); + break; + case OP_AT_S1E0W: + fail = __kvm_at(OP_AT_S1E0W, vaddr); + break; + default: + WARN_ON_ONCE(1); + fail = true; + break; + } + + if (!fail) + par = read_sysreg_par(); + + if (!(vcpu_el2_e2h_is_set(vcpu) && vcpu_el2_tge_is_set(vcpu))) + __mmu_config_restore(&config); + + return par; +} + +void __kvm_at_s1e01(struct kvm_vcpu *vcpu, u32 op, u64 vaddr) +{ + u64 par = __kvm_at_s1e01_fast(vcpu, op, vaddr); + + vcpu_write_sys_reg(vcpu, par, PAR_EL1); +}