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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 7DF8AC04A94 for ; Tue, 8 Aug 2023 11:49:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=1LG/WE9cXfnIK2lrFcEwF48fPyMXjwSJ4Pv+MIJ8vVg=; b=ZaoeT4Iv0jKRiD ssju2i3Hve0z/LAWc0malqKMUiBMVqoWVIt0eczqnXA5PXFRWeTcBI+NmKfYp7xuans52NLe4Qe7x jOFTyYJ29r+eBrbYI9uyDHU9xhjCdtkz37/ipKY7e1PaGj27atdfJ17X33SYN8wpGFCQLj9WqFWL2 bIsz0sIEsSRRAPuib3OSVQ6UVPvs/FgkaJvDfUEMnb7w5tCC3kKzL7oi+ZdGCM6ivA2Egqg1MXFsA xT933ioLg62o/GYDETa0VGAuuC2RlaryIOnhSTLa8manbGt5g1WDW5vlaU6OK5J8TkrwRIgZhHJhw csMWYwSJg0pCIjm7IREg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qTLCY-002VH0-39; Tue, 08 Aug 2023 11:48:39 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qTLCE-002V0n-1w for linux-arm-kernel@lists.infradead.org; Tue, 08 Aug 2023 11:48:27 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D9F2C6250D; Tue, 8 Aug 2023 11:48:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 307C6C433C7; Tue, 8 Aug 2023 11:48:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1691495297; bh=P5QdydtrQ8ywkerynyO9hTpNrICi0GcHa42zU2NtgRs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=C+m24eBnftW/N0vSctu431SM8OyWQ4t8tn751eoP5gLu4IKO/QiJ58/BUXDJStMx5 jRaQM/ZpbYrn/MD5i6HjSYG2cSlCxKLoSCUYj2pWj+SGuXq+tN2ozu0UOh53oxE6FR /4lILddIWgKL63lDC94Bjhiz8U+CqcBr1Mk9ZQXcZHfHVzVYCxj/3PJ/Fj2PSMUUH5 QnQD4p6jupcYckfirayopRgIW+OgEbgDJhp3lnWK8qBTFYrnUAsLKWcHnBO+rZivL8 6Zzf+xy2rYo1+LW/keDqWBRjSRHpOb5uC0qReCWpOutHNH5TrJ30Sx6SqOzo1cLywL yNURUbzUWUc6g== Received: from sofa.misterjones.org ([185.219.108.64] helo=valley-girl.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1qTLBH-0037Ph-Co; Tue, 08 Aug 2023 12:47:19 +0100 From: Marc Zyngier To: kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Catalin Marinas , Eric Auger , Mark Brown , Mark Rutland , Will Deacon , Alexandru Elisei , Andre Przywara , Chase Conklin , Ganapatrao Kulkarni , Darren Hart , Miguel Luis , James Morse , Suzuki K Poulose , Oliver Upton , Zenghui Yu Subject: [PATCH v3 14/27] KVM: arm64: nv: Add trap forwarding infrastructure Date: Tue, 8 Aug 2023 12:46:58 +0100 Message-Id: <20230808114711.2013842-15-maz@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230808114711.2013842-1-maz@kernel.org> References: <20230808114711.2013842-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, eric.auger@redhat.com, broonie@kernel.org, mark.rutland@arm.com, will@kernel.org, alexandru.elisei@arm.com, andre.przywara@arm.com, chase.conklin@arm.com, gankulkarni@os.amperecomputing.com, darren@os.amperecomputing.com, miguel.luis@oracle.com, james.morse@arm.com, suzuki.poulose@arm.com, oliver.upton@linux.dev, yuzenghui@huawei.com 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-20230808_044818_754223_226CB3FD X-CRM114-Status: GOOD ( 31.72 ) 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 A significant part of what a NV hypervisor needs to do is to decide whether a trap from a L2+ guest has to be forwarded to a L1 guest or handled locally. This is done by checking for the trap bits that the guest hypervisor has set and acting accordingly, as described by the architecture. A previous approach was to sprinkle a bunch of checks in all the system register accessors, but this is pretty error prone and doesn't help getting an overview of what is happening. Instead, implement a set of global tables that describe a trap bit, combinations of trap bits, behaviours on trap, and what bits must be evaluated on a system register trap. Although this is painful to describe, this allows to specify each and every control bit in a static manner. To make it efficient, the table is inserted in an xarray that is global to the system, and checked each time we trap a system register while running a L2 guest. Add the basic infrastructure for now, while additional patches will implement configuration registers. Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/kvm_host.h | 1 + arch/arm64/include/asm/kvm_nested.h | 2 + arch/arm64/kvm/emulate-nested.c | 262 ++++++++++++++++++++++++++++ arch/arm64/kvm/sys_regs.c | 6 + arch/arm64/kvm/trace_arm.h | 26 +++ 5 files changed, 297 insertions(+) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 721680da1011..cb1c5c54cedd 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -988,6 +988,7 @@ int kvm_handle_cp10_id(struct kvm_vcpu *vcpu); void kvm_reset_sys_regs(struct kvm_vcpu *vcpu); int __init kvm_sys_reg_table_init(void); +int __init populate_nv_trap_config(void); bool lock_all_vcpus(struct kvm *kvm); void unlock_all_vcpus(struct kvm *kvm); diff --git a/arch/arm64/include/asm/kvm_nested.h b/arch/arm64/include/asm/kvm_nested.h index 8fb67f032fd1..fa23cc9c2adc 100644 --- a/arch/arm64/include/asm/kvm_nested.h +++ b/arch/arm64/include/asm/kvm_nested.h @@ -11,6 +11,8 @@ static inline bool vcpu_has_nv(const struct kvm_vcpu *vcpu) test_bit(KVM_ARM_VCPU_HAS_EL2, vcpu->arch.features)); } +extern bool __check_nv_sr_forward(struct kvm_vcpu *vcpu); + struct sys_reg_params; struct sys_reg_desc; diff --git a/arch/arm64/kvm/emulate-nested.c b/arch/arm64/kvm/emulate-nested.c index b96662029fb1..1b1148770d45 100644 --- a/arch/arm64/kvm/emulate-nested.c +++ b/arch/arm64/kvm/emulate-nested.c @@ -14,6 +14,268 @@ #include "trace.h" +enum trap_behaviour { + BEHAVE_HANDLE_LOCALLY = 0, + BEHAVE_FORWARD_READ = BIT(0), + BEHAVE_FORWARD_WRITE = BIT(1), + BEHAVE_FORWARD_ANY = BEHAVE_FORWARD_READ | BEHAVE_FORWARD_WRITE, +}; + +struct trap_bits { + const enum vcpu_sysreg index; + const enum trap_behaviour behaviour; + const u64 value; + const u64 mask; +}; + +enum trap_group { + /* Indicates no coarse trap control */ + __RESERVED__, + + /* + * The first batch of IDs denote coarse trapping that are used + * on their own instead of being part of a combination of + * trap controls. + */ + + /* + * Anything after this point is a combination of trap controls, + * which all must be evaluated to decide what to do. + */ + __MULTIPLE_CONTROL_BITS__, + + /* + * Anything after this point requires a callback evaluating a + * complex trap condition. Hopefully we'll never need this... + */ + __COMPLEX_CONDITIONS__, + + /* Must be last */ + __NR_TRAP_GROUP_IDS__ +}; + +static const struct trap_bits coarse_trap_bits[] = { +}; + +#define MCB(id, ...) \ + [id - __MULTIPLE_CONTROL_BITS__] = \ + (const enum trap_group []){ \ + __VA_ARGS__, __RESERVED__ \ + } + +static const enum trap_group *coarse_control_combo[] = { +}; + +typedef enum trap_behaviour (*complex_condition_check)(struct kvm_vcpu *); + +#define CCC(id, fn) \ + [id - __COMPLEX_CONDITIONS__] = fn + +static const complex_condition_check ccc[] = { +}; + +/* + * Bit assignment for the trap controls. We use a 64bit word with the + * following layout for each trapped sysreg: + * + * [9:0] enum trap_group (10 bits) + * [13:10] enum fgt_group_id (4 bits) + * [19:14] bit number in the FGT register (6 bits) + * [20] trap polarity (1 bit) + * [62:21] Unused (42 bits) + * [63] RES0 - Must be zero, as lost on insertion in the xarray + */ +#define TC_CGT_BITS 10 +#define TC_FGT_BITS 4 + +union trap_config { + u64 val; + struct { + unsigned long cgt:TC_CGT_BITS; /* Coarse trap id */ + unsigned long fgt:TC_FGT_BITS; /* Fing Grained Trap id */ + unsigned long bit:6; /* Bit number */ + unsigned long pol:1; /* Polarity */ + unsigned long unk:42; /* Unknown */ + unsigned long mbz:1; /* Must Be Zero */ + }; +}; + +struct encoding_to_trap_config { + const u32 encoding; + const u32 end; + const union trap_config tc; +}; + +#define SR_RANGE_TRAP(sr_start, sr_end, trap_id) \ + { \ + .encoding = sr_start, \ + .end = sr_end, \ + .tc = { \ + .cgt = trap_id, \ + }, \ + } + +#define SR_TRAP(sr, trap_id) SR_RANGE_TRAP(sr, sr, trap_id) + +/* + * Map encoding to trap bits for exception reported with EC=0x18. + * These must only be evaluated when running a nested hypervisor, but + * that the current context is not a hypervisor context. When the + * trapped access matches one of the trap controls, the exception is + * re-injected in the nested hypervisor. + */ +static const struct encoding_to_trap_config encoding_to_cgt[] __initconst = { +}; + +static DEFINE_XARRAY(sr_forward_xa); + +static union trap_config get_trap_config(u32 sysreg) +{ + return (union trap_config) { + .val = xa_to_value(xa_load(&sr_forward_xa, sysreg)), + }; +} + +int __init populate_nv_trap_config(void) +{ + int ret = 0; + + BUILD_BUG_ON(sizeof(union trap_config) != sizeof(void *)); + BUILD_BUG_ON(__NR_TRAP_GROUP_IDS__ > BIT(TC_CGT_BITS)); + + for (int i = 0; i < ARRAY_SIZE(encoding_to_cgt); i++) { + const struct encoding_to_trap_config *cgt = &encoding_to_cgt[i]; + void *prev; + + prev = xa_store_range(&sr_forward_xa, cgt->encoding, cgt->end, + xa_mk_value(cgt->tc.val), GFP_KERNEL); + + if (prev) { + kvm_err("Duplicate CGT for (%d, %d, %d, %d, %d)\n", + sys_reg_Op0(cgt->encoding), + sys_reg_Op1(cgt->encoding), + sys_reg_CRn(cgt->encoding), + sys_reg_CRm(cgt->encoding), + sys_reg_Op2(cgt->encoding)); + ret = -EINVAL; + } + } + + kvm_info("nv: %ld coarse grained trap handlers\n", + ARRAY_SIZE(encoding_to_cgt)); + + for (int id = __MULTIPLE_CONTROL_BITS__; + id < (__COMPLEX_CONDITIONS__ - 1); + id++) { + const enum trap_group *cgids; + + cgids = coarse_control_combo[id - __MULTIPLE_CONTROL_BITS__]; + + for (int i = 0; cgids[i] != __RESERVED__; i++) { + if (cgids[i] >= __MULTIPLE_CONTROL_BITS__) { + kvm_err("Recursive MCB %d/%d\n", id, cgids[i]); + ret = -EINVAL; + } + } + } + + if (ret) + xa_destroy(&sr_forward_xa); + + return ret; +} + +static enum trap_behaviour get_behaviour(struct kvm_vcpu *vcpu, + const struct trap_bits *tb) +{ + enum trap_behaviour b = BEHAVE_HANDLE_LOCALLY; + u64 val; + + val = __vcpu_sys_reg(vcpu, tb->index); + if ((val & tb->mask) == tb->value) + b |= tb->behaviour; + + return b; +} + +static enum trap_behaviour __do_compute_trap_behaviour(struct kvm_vcpu *vcpu, + const enum trap_group id, + enum trap_behaviour b) +{ + switch (id) { + const enum trap_group *cgids; + + case __RESERVED__ ... __MULTIPLE_CONTROL_BITS__ - 1: + if (likely(id != __RESERVED__)) + b |= get_behaviour(vcpu, &coarse_trap_bits[id]); + break; + case __MULTIPLE_CONTROL_BITS__ ... __COMPLEX_CONDITIONS__ - 1: + /* Yes, this is recursive. Don't do anything stupid. */ + cgids = coarse_control_combo[id - __MULTIPLE_CONTROL_BITS__]; + for (int i = 0; cgids[i] != __RESERVED__; i++) + b |= __do_compute_trap_behaviour(vcpu, cgids[i], b); + break; + default: + if (ARRAY_SIZE(ccc)) + b |= ccc[id - __COMPLEX_CONDITIONS__](vcpu); + break; + } + + return b; +} + +static enum trap_behaviour compute_trap_behaviour(struct kvm_vcpu *vcpu, + const union trap_config tc) +{ + enum trap_behaviour b = BEHAVE_HANDLE_LOCALLY; + + return __do_compute_trap_behaviour(vcpu, tc.cgt, b); +} + +bool __check_nv_sr_forward(struct kvm_vcpu *vcpu) +{ + union trap_config tc; + enum trap_behaviour b; + bool is_read; + u32 sysreg; + u64 esr; + + if (!vcpu_has_nv(vcpu) || is_hyp_ctxt(vcpu)) + return false; + + esr = kvm_vcpu_get_esr(vcpu); + sysreg = esr_sys64_to_sysreg(esr); + is_read = (esr & ESR_ELx_SYS64_ISS_DIR_MASK) == ESR_ELx_SYS64_ISS_DIR_READ; + + tc = get_trap_config(sysreg); + + /* + * A value of 0 for the whole entry means that we know nothing + * for this sysreg, and that it cannot be forwareded. In this + * situation, let's cut it short. + * + * Note that ultimately, we could also make use of the xarray + * to store the index of the sysreg in the local descriptor + * array, avoiding another search... Hint, hint... + */ + if (!tc.val) + return false; + + b = compute_trap_behaviour(vcpu, tc); + + if (((b & BEHAVE_FORWARD_READ) && is_read) || + ((b & BEHAVE_FORWARD_WRITE) && !is_read)) + goto inject; + + return false; + +inject: + trace_kvm_forward_sysreg_trap(vcpu, sysreg, is_read); + + kvm_inject_nested_sync(vcpu, kvm_vcpu_get_esr(vcpu)); + return true; +} + static u64 kvm_check_illegal_exception_return(struct kvm_vcpu *vcpu, u64 spsr) { u64 mode = spsr & PSR_MODE_MASK; diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index f5baaa508926..dfd72b3a625f 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -3177,6 +3177,9 @@ int kvm_handle_sys_reg(struct kvm_vcpu *vcpu) trace_kvm_handle_sys_reg(esr); + if (__check_nv_sr_forward(vcpu)) + return 1; + params = esr_sys64_to_params(esr); params.regval = vcpu_get_reg(vcpu, Rt); @@ -3594,5 +3597,8 @@ int __init kvm_sys_reg_table_init(void) if (!first_idreg) return -EINVAL; + if (kvm_get_mode() == KVM_MODE_NV) + populate_nv_trap_config(); + return 0; } diff --git a/arch/arm64/kvm/trace_arm.h b/arch/arm64/kvm/trace_arm.h index 6ce5c025218d..8ad53104934d 100644 --- a/arch/arm64/kvm/trace_arm.h +++ b/arch/arm64/kvm/trace_arm.h @@ -364,6 +364,32 @@ TRACE_EVENT(kvm_inject_nested_exception, __entry->hcr_el2) ); +TRACE_EVENT(kvm_forward_sysreg_trap, + TP_PROTO(struct kvm_vcpu *vcpu, u32 sysreg, bool is_read), + TP_ARGS(vcpu, sysreg, is_read), + + TP_STRUCT__entry( + __field(u64, pc) + __field(u32, sysreg) + __field(bool, is_read) + ), + + TP_fast_assign( + __entry->pc = *vcpu_pc(vcpu); + __entry->sysreg = sysreg; + __entry->is_read = is_read; + ), + + TP_printk("%llx %c (%d,%d,%d,%d,%d)", + __entry->pc, + __entry->is_read ? 'R' : 'W', + sys_reg_Op0(__entry->sysreg), + sys_reg_Op1(__entry->sysreg), + sys_reg_CRn(__entry->sysreg), + sys_reg_CRm(__entry->sysreg), + sys_reg_Op2(__entry->sysreg)) +); + #endif /* _TRACE_ARM_ARM64_KVM_H */ #undef TRACE_INCLUDE_PATH -- 2.34.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel