From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Zyngier Subject: Re: [PATCH 21/27] arm64/sve: KVM: Prevent guests from using SVE Date: Tue, 15 Aug 2017 17:33:15 +0100 Message-ID: <0f5b14a8-4d04-61e4-05e8-92cd55c8bee9@arm.com> References: <1502280338-23002-1-git-send-email-Dave.Martin@arm.com> <1502280338-23002-22-git-send-email-Dave.Martin@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1502280338-23002-22-git-send-email-Dave.Martin@arm.com> Content-Language: en-GB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu To: Dave Martin , linux-arm-kernel@lists.infradead.org Cc: linux-arch@vger.kernel.org, libc-alpha@sourceware.org, Ard Biesheuvel , Szabolcs Nagy , Catalin Marinas , Will Deacon , Richard Sandiford , kvmarm@lists.cs.columbia.edu List-Id: linux-arch.vger.kernel.org On 09/08/17 13:05, Dave Martin wrote: > Until KVM has full SVE support, guests must not be allowed to > execute SVE instructions. > > This patch enables the necessary traps, and also ensures that the > traps are disabled again on exit from the guest so that the host > can still use SVE if it wants to. > > Signed-off-by: Dave Martin > --- > arch/arm64/include/asm/kvm_arm.h | 3 ++- > arch/arm64/kvm/hyp/switch.c | 6 +++--- > 2 files changed, 5 insertions(+), 4 deletions(-) > > diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h > index dbf0537..8a19651 100644 > --- a/arch/arm64/include/asm/kvm_arm.h > +++ b/arch/arm64/include/asm/kvm_arm.h > @@ -186,7 +186,7 @@ > #define CPTR_EL2_TTA (1 << 20) > #define CPTR_EL2_TFP (1 << CPTR_EL2_TFP_SHIFT) > #define CPTR_EL2_TZ (1 << 8) > -#define CPTR_EL2_DEFAULT 0x000033ff > +#define CPTR_EL2_DEFAULT (0x000033ff & ~CPTR_EL2_TZ) I must say I'm not overly fond of this construct. I'd rather introduce a RES1 field that matches the v8.2 description, instead of this ugly constant and something that clears it. > > /* Hyp Debug Configuration Register bits */ > #define MDCR_EL2_TPMS (1 << 14) > @@ -237,5 +237,6 @@ > > #define CPACR_EL1_FPEN (3 << 20) > #define CPACR_EL1_TTA (1 << 28) > +#define CPACR_EL1_DEFAULT (CPACR_EL1_FPEN | CPACR_EL1_ZEN_EL1EN) > > #endif /* __ARM64_KVM_ARM_H__ */ > diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c > index 35a90b8..951f3eb 100644 > --- a/arch/arm64/kvm/hyp/switch.c > +++ b/arch/arm64/kvm/hyp/switch.c > @@ -48,7 +48,7 @@ static void __hyp_text __activate_traps_vhe(void) > > val = read_sysreg(cpacr_el1); > val |= CPACR_EL1_TTA; > - val &= ~CPACR_EL1_FPEN; > + val &= ~(CPACR_EL1_FPEN | CPACR_EL1_ZEN); > write_sysreg(val, cpacr_el1); > > write_sysreg(__kvm_hyp_vector, vbar_el1); > @@ -59,7 +59,7 @@ static void __hyp_text __activate_traps_nvhe(void) > u64 val; > > val = CPTR_EL2_DEFAULT; > - val |= CPTR_EL2_TTA | CPTR_EL2_TFP; > + val |= CPTR_EL2_TTA | CPTR_EL2_TFP | CPTR_EL2_TZ; > write_sysreg(val, cptr_el2); > } > > @@ -117,7 +117,7 @@ static void __hyp_text __deactivate_traps_vhe(void) > > write_sysreg(mdcr_el2, mdcr_el2); > write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2); > - write_sysreg(CPACR_EL1_FPEN, cpacr_el1); > + write_sysreg(CPACR_EL1_DEFAULT, cpacr_el1); > write_sysreg(vectors, vbar_el1); > } > > Thanks, M. -- Jazz is not dead. It just smells funny... From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from foss.arm.com ([217.140.101.70]:54580 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752421AbdHOQdT (ORCPT ); Tue, 15 Aug 2017 12:33:19 -0400 Subject: Re: [PATCH 21/27] arm64/sve: KVM: Prevent guests from using SVE References: <1502280338-23002-1-git-send-email-Dave.Martin@arm.com> <1502280338-23002-22-git-send-email-Dave.Martin@arm.com> From: Marc Zyngier Message-ID: <0f5b14a8-4d04-61e4-05e8-92cd55c8bee9@arm.com> Date: Tue, 15 Aug 2017 17:33:15 +0100 MIME-Version: 1.0 In-Reply-To: <1502280338-23002-22-git-send-email-Dave.Martin@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: Dave Martin , linux-arm-kernel@lists.infradead.org Cc: Catalin Marinas , Will Deacon , Ard Biesheuvel , Szabolcs Nagy , Richard Sandiford , kvmarm@lists.cs.columbia.edu, libc-alpha@sourceware.org, linux-arch@vger.kernel.org, Christoffer Dall Message-ID: <20170815163315.uDvZGetS7MsXEAKL5edsU-vBj5PirkFwpTD-i1qpirU@z> On 09/08/17 13:05, Dave Martin wrote: > Until KVM has full SVE support, guests must not be allowed to > execute SVE instructions. > > This patch enables the necessary traps, and also ensures that the > traps are disabled again on exit from the guest so that the host > can still use SVE if it wants to. > > Signed-off-by: Dave Martin > --- > arch/arm64/include/asm/kvm_arm.h | 3 ++- > arch/arm64/kvm/hyp/switch.c | 6 +++--- > 2 files changed, 5 insertions(+), 4 deletions(-) > > diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h > index dbf0537..8a19651 100644 > --- a/arch/arm64/include/asm/kvm_arm.h > +++ b/arch/arm64/include/asm/kvm_arm.h > @@ -186,7 +186,7 @@ > #define CPTR_EL2_TTA (1 << 20) > #define CPTR_EL2_TFP (1 << CPTR_EL2_TFP_SHIFT) > #define CPTR_EL2_TZ (1 << 8) > -#define CPTR_EL2_DEFAULT 0x000033ff > +#define CPTR_EL2_DEFAULT (0x000033ff & ~CPTR_EL2_TZ) I must say I'm not overly fond of this construct. I'd rather introduce a RES1 field that matches the v8.2 description, instead of this ugly constant and something that clears it. > > /* Hyp Debug Configuration Register bits */ > #define MDCR_EL2_TPMS (1 << 14) > @@ -237,5 +237,6 @@ > > #define CPACR_EL1_FPEN (3 << 20) > #define CPACR_EL1_TTA (1 << 28) > +#define CPACR_EL1_DEFAULT (CPACR_EL1_FPEN | CPACR_EL1_ZEN_EL1EN) > > #endif /* __ARM64_KVM_ARM_H__ */ > diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c > index 35a90b8..951f3eb 100644 > --- a/arch/arm64/kvm/hyp/switch.c > +++ b/arch/arm64/kvm/hyp/switch.c > @@ -48,7 +48,7 @@ static void __hyp_text __activate_traps_vhe(void) > > val = read_sysreg(cpacr_el1); > val |= CPACR_EL1_TTA; > - val &= ~CPACR_EL1_FPEN; > + val &= ~(CPACR_EL1_FPEN | CPACR_EL1_ZEN); > write_sysreg(val, cpacr_el1); > > write_sysreg(__kvm_hyp_vector, vbar_el1); > @@ -59,7 +59,7 @@ static void __hyp_text __activate_traps_nvhe(void) > u64 val; > > val = CPTR_EL2_DEFAULT; > - val |= CPTR_EL2_TTA | CPTR_EL2_TFP; > + val |= CPTR_EL2_TTA | CPTR_EL2_TFP | CPTR_EL2_TZ; > write_sysreg(val, cptr_el2); > } > > @@ -117,7 +117,7 @@ static void __hyp_text __deactivate_traps_vhe(void) > > write_sysreg(mdcr_el2, mdcr_el2); > write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2); > - write_sysreg(CPACR_EL1_FPEN, cpacr_el1); > + write_sysreg(CPACR_EL1_DEFAULT, cpacr_el1); > write_sysreg(vectors, vbar_el1); > } > > Thanks, M. -- Jazz is not dead. It just smells funny...