From patchwork Wed May 31 07:24:08 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luca Fancellu X-Patchwork-Id: 13261565 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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 BA20FC77B73 for ; Wed, 31 May 2023 07:24:46 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.541558.844489 (Exim 4.92) (envelope-from ) id 1q4GCE-0006z7-1S; Wed, 31 May 2023 07:24:38 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 541558.844489; Wed, 31 May 2023 07:24:38 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1q4GCD-0006yy-U5; Wed, 31 May 2023 07:24:37 +0000 Received: by outflank-mailman (input) for mailman id 541558; Wed, 31 May 2023 07:24:35 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1q4GCB-0005os-R5 for xen-devel@lists.xenproject.org; Wed, 31 May 2023 07:24:35 +0000 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by se1-gles-flk1.inumbo.com (Halon) with ESMTP id 306acae4-ff84-11ed-8611-37d641c3527e; Wed, 31 May 2023 09:24:33 +0200 (CEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9B9871063; Wed, 31 May 2023 00:25:18 -0700 (PDT) Received: from e125770.cambridge.arm.com (e125770.arm.com [10.1.199.1]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EF2373F663; Wed, 31 May 2023 00:24:31 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 306acae4-ff84-11ed-8611-37d641c3527e From: Luca Fancellu To: xen-devel@lists.xenproject.org Cc: bertrand.marquis@arm.com, wei.chen@arm.com, Andrew Cooper , George Dunlap , Jan Beulich , Julien Grall , Stefano Stabellini , Wei Liu , Volodymyr Babchuk Subject: [PATCH v8 07/12] xen: enable Dom0 to use SVE feature Date: Wed, 31 May 2023 08:24:08 +0100 Message-Id: <20230531072413.868673-8-luca.fancellu@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230531072413.868673-1-luca.fancellu@arm.com> References: <20230531072413.868673-1-luca.fancellu@arm.com> MIME-Version: 1.0 Add a command line parameter to allow Dom0 the use of SVE resources, the command line parameter sve=, sub argument of dom0=, controls the feature on this domain and sets the maximum SVE vector length for Dom0. Add a new function, parse_signed_integer(), to parse an integer command line argument. Signed-off-by: Luca Fancellu Reviewed-by: Jan Beulich # !arm Reviewed-by: Bertrand Marquis --- Changes from v7: - Fixed documentation, add R-by Jan and Bertrand Changes from v6: - Fixed case for e==NULL in parse_signed_integer, drop parenthesis from if conditions, delete inline sve_domctl_vl_param and rely on DCE from the compiler (Jan) - Drop parenthesis from opt_dom0_sve (Julien) - Do not continue if 'sve' is in command line args but CONFIG_ARM64_SVE is not selected: https://lore.kernel.org/all/7614AE25-F59D-430A-9C3E-30B1CE0E1580@arm.com/ Changes from v5: - stop the domain if VL error occurs (Julien, Bertrand) - update the documentation - Rename sve_sanitize_vl_param to sve_domctl_vl_param to mark the fact that we are sanitizing a parameter coming from the user before encoding it into sve_vl in domctl structure. (suggestion from Bertrand in a separate discussion) - update comment in parse_signed_integer, return boolean in sve_domctl_vl_param (Jan). Changes from v4: - Negative values as user param means max supported HW VL (Jan) - update documentation, make use of no_config_param(), rename parse_integer into parse_signed_integer and take long long *, also put a comment on the -2 return condition, update declaration comment to reflect the modifications (Jan) Changes from v3: - Don't use fixed len types when not needed (Jan) - renamed domainconfig_encode_vl to sve_encode_vl - Use a sub argument of dom0= to enable the feature (Jan) - Add parse_integer() function Changes from v2: - xen_domctl_createdomain field has changed into sve_vl and its value now is the VL / 128, create an helper function for that. Changes from v1: - No changes Changes from RFC: - Changed docs to explain that the domain won't be created if the requested vector length is above the supported one from the platform. --- docs/misc/xen-command-line.pandoc | 20 ++++++++++++++++++-- xen/arch/arm/arm64/sve.c | 20 ++++++++++++++++++++ xen/arch/arm/domain_build.c | 26 ++++++++++++++++++++++++++ xen/arch/arm/include/asm/arm64/sve.h | 10 ++++++++++ xen/common/kernel.c | 28 ++++++++++++++++++++++++++++ xen/include/xen/lib.h | 10 ++++++++++ 6 files changed, 112 insertions(+), 2 deletions(-) diff --git a/docs/misc/xen-command-line.pandoc b/docs/misc/xen-command-line.pandoc index e0b89b7d3319..4060ebdc5d76 100644 --- a/docs/misc/xen-command-line.pandoc +++ b/docs/misc/xen-command-line.pandoc @@ -777,9 +777,9 @@ Specify the bit width of the DMA heap. ### dom0 = List of [ pv | pvh, shadow=, verbose=, - cpuid-faulting=, msr-relaxed= ] + cpuid-faulting=, msr-relaxed= ] (x86) - Applicability: x86 + = List of [ sve= ] (Arm64) Controls for how dom0 is constructed on x86 systems. @@ -838,6 +838,22 @@ Controls for how dom0 is constructed on x86 systems. If using this option is necessary to fix an issue, please report a bug. +Enables features on dom0 on Arm systems. + +* The `sve` integer parameter enables Arm SVE usage for Dom0 and sets the + maximum SVE vector length, the option is applicable only to Arm64 Dom0 + kernels. + A value equal to 0 disables the feature, this is the default value. + Values below 0 means the feature uses the maximum SVE vector length + supported by hardware, if SVE is supported. + Values above 0 explicitly set the maximum SVE vector length for Dom0, + allowed values are from 128 to maximum 2048, being multiple of 128. + Please note that when the user explicitly specifies the value, if that value + is above the hardware supported maximum SVE vector length, the domain + creation will fail and the system will stop, the same will occur if the + option is provided with a positive non zero value, but the platform doesn't + support SVE. + ### dom0-cpuid = List of comma separated booleans diff --git a/xen/arch/arm/arm64/sve.c b/xen/arch/arm/arm64/sve.c index 56d8f27ea26a..23a9d0ba661c 100644 --- a/xen/arch/arm/arm64/sve.c +++ b/xen/arch/arm/arm64/sve.c @@ -13,6 +13,9 @@ #include #include +/* opt_dom0_sve: allow Dom0 to use SVE and set maximum vector length. */ +int __initdata opt_dom0_sve; + extern unsigned int sve_get_hw_vl(void); /* @@ -152,6 +155,23 @@ void sve_restore_state(struct vcpu *v) sve_load_ctx(v->arch.vfp.sve_zreg_ctx_end, v->arch.vfp.fpregs, 1); } +bool __init sve_domctl_vl_param(int val, unsigned int *out) +{ + /* + * Negative SVE parameter value means to use the maximum supported + * vector length, otherwise if a positive value is provided, check if the + * vector length is a multiple of 128 + */ + if ( val < 0 ) + *out = get_sys_vl_len(); + else if ( (val % SVE_VL_MULTIPLE_VAL) == 0 ) + *out = val; + else + return false; + + return true; +} + /* * Local variables: * mode: C diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c index e2f063991423..14b42120a9b1 100644 --- a/xen/arch/arm/domain_build.c +++ b/xen/arch/arm/domain_build.c @@ -62,6 +62,22 @@ custom_param("dom0_mem", parse_dom0_mem); int __init parse_arch_dom0_param(const char *s, const char *e) { + long long val; + + if ( !parse_signed_integer("sve", s, e, &val) ) + { +#ifdef CONFIG_ARM64_SVE + if ( (val >= INT_MIN) && (val <= INT_MAX) ) + opt_dom0_sve = val; + else + printk(XENLOG_INFO "'sve=%lld' value out of range!\n", val); + + return 0; +#else + panic("'sve' property found, but CONFIG_ARM64_SVE not selected"); +#endif + } + return -EINVAL; } @@ -4134,6 +4150,16 @@ void __init create_dom0(void) if ( iommu_enabled ) dom0_cfg.flags |= XEN_DOMCTL_CDF_iommu; + if ( opt_dom0_sve ) + { + unsigned int vl; + + if ( sve_domctl_vl_param(opt_dom0_sve, &vl) ) + dom0_cfg.arch.sve_vl = sve_encode_vl(vl); + else + panic("SVE vector length error\n"); + } + dom0 = domain_create(0, &dom0_cfg, CDF_privileged | CDF_directmap); if ( IS_ERR(dom0) ) panic("Error creating domain 0 (rc = %ld)\n", PTR_ERR(dom0)); diff --git a/xen/arch/arm/include/asm/arm64/sve.h b/xen/arch/arm/include/asm/arm64/sve.h index 65b46685d263..a71d6a295dcc 100644 --- a/xen/arch/arm/include/asm/arm64/sve.h +++ b/xen/arch/arm/include/asm/arm64/sve.h @@ -21,14 +21,22 @@ static inline unsigned int sve_decode_vl(unsigned int sve_vl) return sve_vl * SVE_VL_MULTIPLE_VAL; } +static inline unsigned int sve_encode_vl(unsigned int sve_vl_bits) +{ + return sve_vl_bits / SVE_VL_MULTIPLE_VAL; +} + register_t compute_max_zcr(void); int sve_context_init(struct vcpu *v); void sve_context_free(struct vcpu *v); void sve_save_state(struct vcpu *v); void sve_restore_state(struct vcpu *v); +bool sve_domctl_vl_param(int val, unsigned int *out); #ifdef CONFIG_ARM64_SVE +extern int opt_dom0_sve; + static inline bool is_sve_domain(const struct domain *d) { return d->arch.sve_vl > 0; @@ -38,6 +46,8 @@ unsigned int get_sys_vl_len(void); #else /* !CONFIG_ARM64_SVE */ +#define opt_dom0_sve 0 + static inline bool is_sve_domain(const struct domain *d) { return false; diff --git a/xen/common/kernel.c b/xen/common/kernel.c index f7b1f65f373c..7cd00a4c999a 100644 --- a/xen/common/kernel.c +++ b/xen/common/kernel.c @@ -314,6 +314,34 @@ int parse_boolean(const char *name, const char *s, const char *e) return -1; } +int __init parse_signed_integer(const char *name, const char *s, const char *e, + long long *val) +{ + size_t slen, nlen; + const char *str; + long long pval; + + slen = e ? ({ ASSERT(e >= s); e - s; }) : strlen(s); + nlen = strlen(name); + + if ( !e ) + e = s + slen; + + /* Check that this is the name we're looking for and a value was provided */ + if ( slen <= nlen || strncmp(s, name, nlen) || s[nlen] != '=' ) + return -1; + + pval = simple_strtoll(&s[nlen + 1], &str, 10); + + /* Number not recognised */ + if ( str != e ) + return -2; + + *val = pval; + + return 0; +} + int cmdline_strcmp(const char *frag, const char *name) { for ( ; ; frag++, name++ ) diff --git a/xen/include/xen/lib.h b/xen/include/xen/lib.h index e914ccade095..5343ee7a944a 100644 --- a/xen/include/xen/lib.h +++ b/xen/include/xen/lib.h @@ -94,6 +94,16 @@ int parse_bool(const char *s, const char *e); */ int parse_boolean(const char *name, const char *s, const char *e); +/** + * Given a specific name, parses a string of the form: + * $NAME= + * returning 0 and a value in val, for a recognised integer. + * Returns -1 for name not found, general errors, or -2 if name is found but + * not recognised number. + */ +int parse_signed_integer(const char *name, const char *s, const char *e, + long long *val); + /** * Very similar to strcmp(), but will declare a match if the NUL in 'name' * lines up with comma, colon, semicolon or equals in 'frag'. Designed for