From patchwork Thu Jun 13 20:17:42 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Upton X-Patchwork-Id: 13697427 Received: from out-175.mta1.migadu.com (out-175.mta1.migadu.com [95.215.58.175]) (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 17DFD137921 for ; Thu, 13 Jun 2024 20:18:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.175 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718309916; cv=none; b=U6zmexY/Ts6aUZwzGIdf8iov7CBDtFpqr04wnTpLzKAp0OmuhD1lTeQggilEJ5rgQijNcQUqWIpKWSdZQHVbaboWz0utVCNo5wd0cKD57Kjxwe/ymcBUFNsvW4VIGTqDML1eiXpr3jiNCsgU0G8Sx7Mz4vIPddJa6+OrEIadFQY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718309916; c=relaxed/simple; bh=GwJsvjwl7zNurwJ8mNA8dq3D++FdhA0cL2XFCZke+vk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Rcq+8QSZzCIHzyQnzE2V/0i8vjif55/P5tOom8v3ODPESvcP4naxGn9VYRR1XQk4YN1JLOpwbIX4SJ1OxRGoX5kDH9BqtoOXvLl+a/CyuLf8KQ4oSJearROPg0bZ8ssGqIQsWvFc3jHixYsq+Yzqz3MZJzZHmAuzurZ6lV008Zk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=jqETHA9w; arc=none smtp.client-ip=95.215.58.175 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="jqETHA9w" X-Envelope-To: kvmarm@lists.linux.dev DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1718309911; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=f/xSMgIWdeZ30IzTVLz5ZirzNq0I0wkqI7ZRNXe0Bw4=; b=jqETHA9wrDLnd+lfznIlcSRL9AmZK8L+uNomZD06leSLkkscIdgv/O5Ln5r+6+k014a62Q cxjC00prtMFa0c4AFvpUQCtG9FvjKn6Ez9BLDapdIX8DM3yW8ejEI1Q93tuX5tYgvqNp6C /uxLAL66OhzKnBh0wQWldpEpC6S7EzQ= X-Envelope-To: maz@kernel.org X-Envelope-To: james.morse@arm.com X-Envelope-To: suzuki.poulose@arm.com X-Envelope-To: yuzenghui@huawei.com X-Envelope-To: kvm@vger.kernel.org X-Envelope-To: tabba@google.com X-Envelope-To: jintack.lim@linaro.org X-Envelope-To: christoffer.dall@arm.com X-Envelope-To: oliver.upton@linux.dev X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Oliver Upton To: kvmarm@lists.linux.dev Cc: Marc Zyngier , James Morse , Suzuki K Poulose , Zenghui Yu , kvm@vger.kernel.org, Fuad Tabba , Jintack Lim , Christoffer Dall , Oliver Upton Subject: [PATCH v2 01/15] KVM: arm64: nv: Forward FP/ASIMD traps to guest hypervisor Date: Thu, 13 Jun 2024 20:17:42 +0000 Message-ID: <20240613201756.3258227-2-oliver.upton@linux.dev> In-Reply-To: <20240613201756.3258227-1-oliver.upton@linux.dev> References: <20240613201756.3258227-1-oliver.upton@linux.dev> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT From: Jintack Lim Give precedence to the guest hypervisor's trap configuration when routing an FP/ASIMD trap taken to EL2. Take advantage of the infrastructure for translating CPTR_EL2 into the VHE (i.e. EL1) format and base the trap decision solely on the VHE view of the register. The in-memory value of CPTR_EL2 will always be up to date for the guest hypervisor (more on that later), so just read it directly from memory. Bury all of this behind a macro keyed off of the CPTR bitfield in anticipation of supporting other traps (e.g. SVE). Signed-off-by: Jintack Lim Signed-off-by: Christoffer Dall [maz: account for HCR_EL2.E2H when testing for TFP/FPEN, with all the hard work actually being done by Chase Conklin] Signed-off-by: Marc Zyngier [ oliver: translate nVHE->VHE format for testing traps; macro for reuse in other CPTR_EL2.xEN fields ] Signed-off-by: Oliver Upton Reviewed-by: Marc Zyngier --- arch/arm64/include/asm/kvm_emulate.h | 43 +++++++++++++++++++++++++ arch/arm64/include/asm/kvm_nested.h | 1 - arch/arm64/kvm/handle_exit.c | 16 ++++++--- arch/arm64/kvm/hyp/include/hyp/switch.h | 3 ++ 4 files changed, 58 insertions(+), 5 deletions(-) diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index 501e3e019c93..c3c5a5999ed7 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -11,6 +11,7 @@ #ifndef __ARM64_KVM_EMULATE_H__ #define __ARM64_KVM_EMULATE_H__ +#include #include #include @@ -599,4 +600,46 @@ static __always_inline void kvm_reset_cptr_el2(struct kvm_vcpu *vcpu) kvm_write_cptr_el2(val); } + +/* + * Returns a 'sanitised' view of CPTR_EL2, translating from nVHE to the VHE + * format if E2H isn't set. + */ +static inline u64 vcpu_sanitised_cptr_el2(const struct kvm_vcpu *vcpu) +{ + u64 cptr = __vcpu_sys_reg(vcpu, CPTR_EL2); + + if (!vcpu_el2_e2h_is_set(vcpu)) + cptr = translate_cptr_el2_to_cpacr_el1(cptr); + + return cptr; +} + +static inline bool ____cptr_xen_trap_enabled(const struct kvm_vcpu *vcpu, + unsigned int xen) +{ + switch (xen) { + case 0b00: + case 0b10: + return true; + case 0b01: + return vcpu_el2_tge_is_set(vcpu) && !vcpu_is_el2(vcpu); + case 0b11: + default: + return false; + } +} + +#define __guest_hyp_cptr_xen_trap_enabled(vcpu, xen) \ + (!vcpu_has_nv(vcpu) ? false : \ + ____cptr_xen_trap_enabled(vcpu, \ + SYS_FIELD_GET(CPACR_ELx, xen, \ + vcpu_sanitised_cptr_el2(vcpu)))) + +static inline bool guest_hyp_fpsimd_traps_enabled(const struct kvm_vcpu *vcpu) +{ + return __guest_hyp_cptr_xen_trap_enabled(vcpu, FPEN); +} + + #endif /* __ARM64_KVM_EMULATE_H__ */ diff --git a/arch/arm64/include/asm/kvm_nested.h b/arch/arm64/include/asm/kvm_nested.h index 5e0ab0596246..5d55f76254c3 100644 --- a/arch/arm64/include/asm/kvm_nested.h +++ b/arch/arm64/include/asm/kvm_nested.h @@ -75,5 +75,4 @@ static inline bool kvm_auth_eretax(struct kvm_vcpu *vcpu, u64 *elr) return false; } #endif - #endif /* __ARM64_KVM_NESTED_H */ diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index b037f0a0e27e..59fe9b10a87a 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -94,11 +94,19 @@ static int handle_smc(struct kvm_vcpu *vcpu) } /* - * Guest access to FP/ASIMD registers are routed to this handler only - * when the system doesn't support FP/ASIMD. + * This handles the cases where the system does not support FP/ASIMD or when + * we are running nested virtualization and the guest hypervisor is trapping + * FP/ASIMD accesses by its guest guest. + * + * All other handling of guest vs. host FP/ASIMD register state is handled in + * fixup_guest_exit(). */ -static int handle_no_fpsimd(struct kvm_vcpu *vcpu) +static int kvm_handle_fpasimd(struct kvm_vcpu *vcpu) { + if (guest_hyp_fpsimd_traps_enabled(vcpu)) + return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_esr(vcpu)); + + /* This is the case when the system doesn't support FP/ASIMD. */ kvm_inject_undefined(vcpu); return 1; } @@ -304,7 +312,7 @@ static exit_handle_fn arm_exit_handlers[] = { [ESR_ELx_EC_BREAKPT_LOW]= kvm_handle_guest_debug, [ESR_ELx_EC_BKPT32] = kvm_handle_guest_debug, [ESR_ELx_EC_BRK64] = kvm_handle_guest_debug, - [ESR_ELx_EC_FP_ASIMD] = handle_no_fpsimd, + [ESR_ELx_EC_FP_ASIMD] = kvm_handle_fpasimd, [ESR_ELx_EC_PAC] = kvm_handle_ptrauth, }; diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h index a92566f36022..b302d32f8326 100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -341,6 +341,9 @@ static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code) /* Only handle traps the vCPU can support here: */ switch (esr_ec) { case ESR_ELx_EC_FP_ASIMD: + /* Forward traps to the guest hypervisor as required */ + if (guest_hyp_fpsimd_traps_enabled(vcpu)) + return false; break; case ESR_ELx_EC_SVE: if (!sve_guest)