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 X-Spam-Level: X-Spam-Status: No, score=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 968BCC4360F for ; Thu, 21 Feb 2019 15:51:00 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 66E5120855 for ; Thu, 21 Feb 2019 15:51:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="cUasee8U" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 66E5120855 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=NIzA8KU2UMEMbKJGI8MBBWUHLj/QJI5rJmY3j96MYe0=; b=cUasee8UGQ1A3P 2SNFgGdm0/SPbdzkwtqxR43H4rizNPDuHQ/d5hKkEOxBqrsrTIMWFOWZ+axSKJ5rHSCZtRulpptFR Q2BWDa0DL+koU1+Eyoogxn1S+lPm2DUIw/bpJRJl+pFz4BNx4XRhRL4r0zJ7pveGkGv8UBBgJRekR zcd5eR1d/i0DMre7pfsKh5caF3mIh6htWcNRpzgNYa7gLMv9RinlLYkdXcorsl3nNFlJmNFRp7c6w pPwSFYwQd3AwqQ+3OP8q88ZHDD0ufv6ux1LS+AMhHHLjSSz1hzYp6gIuUH6aXOcmlypcshgJMaXRe IZPA/QvXKKHdY58DRpgw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gwqcj-00037d-Dw; Thu, 21 Feb 2019 15:50:57 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gwqbW-0000mK-Ts for linux-arm-kernel@lists.infradead.org; Thu, 21 Feb 2019 15:49:44 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2A0CBA78; Thu, 21 Feb 2019 07:49:40 -0800 (PST) Received: from e103592.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3B1DB3F5C1; Thu, 21 Feb 2019 07:49:38 -0800 (PST) Date: Thu, 21 Feb 2019 15:49:35 +0000 From: Dave Martin To: Amit Daniel Kachhap Subject: Re: [PATCH v6 1/6] arm64/kvm: preserve host HCR_EL2 value Message-ID: <20190221154935.GU3567@e103592.cambridge.arm.com> References: <1550568271-5319-1-git-send-email-amit.kachhap@arm.com> <1550568271-5319-2-git-send-email-amit.kachhap@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1550568271-5319-2-git-send-email-amit.kachhap@arm.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190221_074942_978283_210B9722 X-CRM114-Status: GOOD ( 29.81 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Marc Zyngier , Catalin Marinas , Will Deacon , linux-kernel@vger.kernel.org, Kristina Martsenko , Ramana Radhakrishnan , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Feb 19, 2019 at 02:54:26PM +0530, Amit Daniel Kachhap wrote: > From: Mark Rutland > > When restoring HCR_EL2 for the host, KVM uses HCR_HOST_VHE_FLAGS, which > is a constant value. This works today, as the host HCR_EL2 value is > always the same, but this will get in the way of supporting extensions > that require HCR_EL2 bits to be set conditionally for the host. > > To allow such features to work without KVM having to explicitly handle > every possible host feature combination, this patch has KVM save/restore > for the host HCR when switching to/from a guest HCR. The saving of the > register is done once during cpu hypervisor initialization state and is > just restored after switch from guest. > > For fetching HCR_EL2 during kvm initialisation, a hyp call is made using > kvm_call_hyp and is helpful in NHVE case. Minor nit: NVHE misspelled. This looks a bit like it's naming an arch feature rather than a kernel implementation detail though. Maybe write "non-VHE". > For the hyp TLB maintenance code, __tlb_switch_to_host_vhe() is updated > to toggle the TGE bit with a RMW sequence, as we already do in > __tlb_switch_to_guest_vhe(). > > The value of hcr_el2 is now stored in struct kvm_cpu_context as both host > and guest can now use this field in a common way. > > Signed-off-by: Mark Rutland > [Added __cpu_copy_hyp_conf, hcr_el2 field in struct kvm_cpu_context] > Signed-off-by: Amit Daniel Kachhap > Cc: Marc Zyngier > Cc: Christoffer Dall > Cc: kvmarm@lists.cs.columbia.edu > --- > arch/arm/include/asm/kvm_host.h | 2 ++ > arch/arm64/include/asm/kvm_asm.h | 2 ++ > arch/arm64/include/asm/kvm_emulate.h | 22 +++++++++++----------- > arch/arm64/include/asm/kvm_host.h | 13 ++++++++++++- > arch/arm64/include/asm/kvm_hyp.h | 2 +- > arch/arm64/kvm/guest.c | 2 +- > arch/arm64/kvm/hyp/switch.c | 23 +++++++++++++---------- > arch/arm64/kvm/hyp/sysreg-sr.c | 21 ++++++++++++++++++++- > arch/arm64/kvm/hyp/tlb.c | 6 +++++- > virt/kvm/arm/arm.c | 1 + > 10 files changed, 68 insertions(+), 26 deletions(-) > > diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h > index ca56537..05706b4 100644 > --- a/arch/arm/include/asm/kvm_host.h > +++ b/arch/arm/include/asm/kvm_host.h > @@ -273,6 +273,8 @@ static inline void __cpu_init_stage2(void) > kvm_call_hyp(__init_stage2_translation); > } > > +static inline void __cpu_copy_hyp_conf(void) {} > + > static inline int kvm_arch_vm_ioctl_check_extension(struct kvm *kvm, long ext) > { > return 0; > diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h > index f5b79e9..8acd73f 100644 > --- a/arch/arm64/include/asm/kvm_asm.h > +++ b/arch/arm64/include/asm/kvm_asm.h > @@ -80,6 +80,8 @@ extern void __vgic_v3_init_lrs(void); > > extern u32 __kvm_get_mdcr_el2(void); > > +extern void __kvm_populate_host_regs(void); > + > /* Home-grown __this_cpu_{ptr,read} variants that always work at HYP */ > #define __hyp_this_cpu_ptr(sym) \ > ({ \ > diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h > index 506386a..0dbe795 100644 > --- a/arch/arm64/include/asm/kvm_emulate.h > +++ b/arch/arm64/include/asm/kvm_emulate.h > @@ -50,25 +50,25 @@ void kvm_inject_pabt32(struct kvm_vcpu *vcpu, unsigned long addr); > > static inline bool vcpu_el1_is_32bit(struct kvm_vcpu *vcpu) > { > - return !(vcpu->arch.hcr_el2 & HCR_RW); > + return !(vcpu->arch.ctxt.hcr_el2 & HCR_RW); Putting hcr_el2 into struct kvm_cpu_context creates a lot of splatter here, and I'm wondering whether it's really necessary. Otherwise, we could just put the per-vcpu guest HCR_EL2 value in struct kvm_vcpu_arch. Is the *host* hcr_el2 value really different per-vcpu? That looks odd. I would have thought this is fixed across the system at KVM startup time. Having a single global host hcr_el2 would also avoid the need for __kvm_populate_host_regs(): instead, we just decide what HCR_EL2 is to be ahead of time and set a global variable that we map into Hyp. Or does the host HCR_EL2 need to vary at runtime for some reason I've missed? [...] +void __hyp_text __kvm_populate_host_regs(void) +{ + struct kvm_cpu_context *host_ctxt; + + if (has_vhe()) + host_ctxt = this_cpu_ptr(&kvm_host_cpu_state); + else + host_ctxt = __hyp_this_cpu_ptr(kvm_host_cpu_state); According to the comment by the definition of __hyp_this_cpu_ptr(), this always works at Hyp. I also see other calls with no fallback this_cpu_ptr() call like we have here. So, can we simply always call __hyp_this_cpu_ptr() here? (I'm not familiar with this, myself.) Cheers ---Dave _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel