Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932946AbdGSQD7 (ORCPT ); Wed, 19 Jul 2017 12:03:59 -0400 Received: from foss.arm.com ([217.140.101.70]:42374 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933276AbdGSQDR (ORCPT ); Wed, 19 Jul 2017 12:03:17 -0400 From: Mark Rutland To: linux-arm-kernel@lists.infradead.org Cc: arnd@arndb.de, catalin.marinas@arm.com, christoffer.dall@linaro.org, Dave.Martin@arm.com, jiong.wang@arm.com, kvmarm@lists.cs.columbia.edu, linux-arch@vger.kernel.org, marc.zyngier@arm.com, mark.rutland@arm.com, suzuki.poulose@arm.com, will.deacon@arm.com, yao.qi@arm.com, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com Subject: [PATCH 09/11] arm64/kvm: preserve host HCR_EL2 value Date: Wed, 19 Jul 2017 17:01:30 +0100 Message-Id: <1500480092-28480-10-git-send-email-mark.rutland@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1500480092-28480-1-git-send-email-mark.rutland@arm.com> References: <1500480092-28480-1-git-send-email-mark.rutland@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4301 Lines: 124 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 the host HCR when switching to/from a guest HCR. For __{activate,deactivate}_traps(), the HCR save/restore is made common across the !VHE and VHE paths. As the host and guest HCR values must have E2H set when VHE is in use, register redirection should always be in effect at EL2, and this change should not adversely affect the VHE code. 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 now unused HCR_HOST_VHE_FLAGS definition is removed. Signed-off-by: Mark Rutland Cc: Christoffer Dall Cc: Marc Zyngier Cc: kvmarm@lists.cs.columbia.edu --- arch/arm64/include/asm/kvm_arm.h | 1 - arch/arm64/include/asm/kvm_host.h | 5 ++++- arch/arm64/kvm/hyp/switch.c | 5 +++-- arch/arm64/kvm/hyp/tlb.c | 6 +++++- 4 files changed, 12 insertions(+), 5 deletions(-) diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h index c1267e8..7b9c898 100644 --- a/arch/arm64/include/asm/kvm_arm.h +++ b/arch/arm64/include/asm/kvm_arm.h @@ -84,7 +84,6 @@ HCR_AMO | HCR_SWIO | HCR_TIDCP | HCR_RW) #define HCR_VIRT_EXCP_MASK (HCR_VSE | HCR_VI | HCR_VF) #define HCR_INT_OVERRIDE (HCR_FMO | HCR_IMO) -#define HCR_HOST_VHE_FLAGS (HCR_RW | HCR_TGE | HCR_E2H) /* TCR_EL2 Registers bits */ #define TCR_EL2_RES1 ((1 << 31) | (1 << 23)) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index d686300..0d7c3dd 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -198,10 +198,13 @@ struct kvm_cpu_context { struct kvm_vcpu_arch { struct kvm_cpu_context ctxt; - /* HYP configuration */ + /* Guest HYP configuration */ u64 hcr_el2; u32 mdcr_el2; + /* Host HYP configuration */ + u64 host_hcr_el2; + /* Exception Information */ struct kvm_vcpu_fault_info fault; diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index 945e79c..6108813 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -71,6 +71,8 @@ static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu) { u64 val; + vcpu->arch.host_hcr_el2 = read_sysreg(hcr_el2); + /* * We are about to set CPTR_EL2.TFP to trap all floating point * register accesses to EL2, however, the ARM ARM clearly states that @@ -110,7 +112,6 @@ static void __hyp_text __deactivate_traps_vhe(void) MDCR_EL2_TPMS; write_sysreg(mdcr_el2, mdcr_el2); - write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2); write_sysreg(CPACR_EL1_FPEN, cpacr_el1); write_sysreg(vectors, vbar_el1); } @@ -123,7 +124,6 @@ static void __hyp_text __deactivate_traps_nvhe(void) mdcr_el2 |= MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT; write_sysreg(mdcr_el2, mdcr_el2); - write_sysreg(HCR_RW, hcr_el2); write_sysreg(CPTR_EL2_DEFAULT, cptr_el2); } @@ -145,6 +145,7 @@ static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu) __deactivate_traps_arch()(); write_sysreg(0, hstr_el2); write_sysreg(0, pmuserenr_el0); + write_sysreg(vcpu->arch.host_hcr_el2, hcr_el2); } static void __hyp_text __activate_vm(struct kvm_vcpu *vcpu) diff --git a/arch/arm64/kvm/hyp/tlb.c b/arch/arm64/kvm/hyp/tlb.c index 73464a9..c2b0680 100644 --- a/arch/arm64/kvm/hyp/tlb.c +++ b/arch/arm64/kvm/hyp/tlb.c @@ -49,12 +49,16 @@ static hyp_alternate_select(__tlb_switch_to_guest, static void __hyp_text __tlb_switch_to_host_vhe(struct kvm *kvm) { + u64 val; + /* * We're done with the TLB operation, let's restore the host's * view of HCR_EL2. */ write_sysreg(0, vttbr_el2); - write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2); + val = read_sysreg(hcr_el2); + val |= HCR_TGE; + write_sysreg(val, hcr_el2); } static void __hyp_text __tlb_switch_to_host_nvhe(struct kvm *kvm) -- 1.9.1