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Mon, 18 Mar 2024 11:47:15 +0000 Date: Mon, 18 Mar 2024 11:47:14 +0000 Message-ID: <861q87224d.wl-maz@kernel.org> From: Marc Zyngier To: Sebastian Ott Cc: linux-arm-kernel@lists.infradead.org, Oliver Upton Subject: Re: [PATCH 2/4] KVM: arm64: ensure guest access to CTR_EL0 is trapped In-Reply-To: <20240318111636.10613-3-sebott@redhat.com> References: <20240318111636.10613-1-sebott@redhat.com> <20240318111636.10613-3-sebott@redhat.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/29.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: sebott@redhat.com, linux-arm-kernel@lists.infradead.org, oliver.upton@linux.dev X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240318_044718_338357_DDF1A1FF X-CRM114-Status: GOOD ( 17.55 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, 18 Mar 2024 11:16:34 +0000, Sebastian Ott wrote: > > Ensure that guest access to the CTR_EL0 register is trapped > independent of cpu errata. > > Signed-off-by: Sebastian Ott > --- > arch/arm64/include/asm/kvm_emulate.h | 7 +------ > 1 file changed, 1 insertion(+), 6 deletions(-) > > diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h > index b804fe832184..daaaf7664219 100644 > --- a/arch/arm64/include/asm/kvm_emulate.h > +++ b/arch/arm64/include/asm/kvm_emulate.h > @@ -91,12 +91,7 @@ static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu) > vcpu->arch.hcr_el2 |= HCR_TVM; > } > > - if (cpus_have_final_cap(ARM64_HAS_EVT) && > - !cpus_have_final_cap(ARM64_MISMATCHED_CACHE_TYPE)) > - vcpu->arch.hcr_el2 |= HCR_TID4; > - else > - vcpu->arch.hcr_el2 |= HCR_TID2; > - > + vcpu->arch.hcr_el2 |= HCR_TID2; NAK. This is a huge performance sync. You should only revert to this when absolutely necessary. M. -- Without deviation from the norm, progress is not possible. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel