Add a command line parameter to allow Dom0 the use of SVE resources, the command line parameter sve=<integer>, 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 <luca.fance...@arm.com> --- 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 | 18 ++++++++++++++++-- xen/arch/arm/arm64/sve.c | 21 +++++++++++++++++++++ xen/arch/arm/domain_build.c | 27 +++++++++++++++++++++++++++ xen/arch/arm/include/asm/arm64/sve.h | 15 +++++++++++++++ xen/common/kernel.c | 25 +++++++++++++++++++++++++ xen/include/xen/lib.h | 10 ++++++++++ 6 files changed, 114 insertions(+), 2 deletions(-) diff --git a/docs/misc/xen-command-line.pandoc b/docs/misc/xen-command-line.pandoc index e0b89b7d3319..9c0790ce6c7c 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=<bool>, verbose=<bool>, - cpuid-faulting=<bool>, msr-relaxed=<bool> ] + cpuid-faulting=<bool>, msr-relaxed=<bool> ] (x86) - Applicability: x86 + = List of [ sve=<integer> ] (Arm) Controls for how dom0 is constructed on x86 systems. @@ -838,6 +838,20 @@ 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 domain and sets + the maximum SVE vector length. + 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, please be aware that if the hardware doesn't supports + SVE, the feature remains disabled. + 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 specify the value, if that value + is above the hardware supported maximum SVE vector length, the domain + creation will fail and the system will stop. + ### dom0-cpuid = List of comma separated booleans diff --git a/xen/arch/arm/arm64/sve.c b/xen/arch/arm/arm64/sve.c index 5485648850a0..ad5db62e1805 100644 --- a/xen/arch/arm/arm64/sve.c +++ b/xen/arch/arm/arm64/sve.c @@ -9,6 +9,9 @@ #include <xen/sizes.h> #include <asm/arm64/sve.h> +/* 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); extern void sve_save_ctx(uint64_t *sve_ctx, uint64_t *pregs, int save_ffr); extern void sve_load_ctx(uint64_t const *sve_ctx, uint64_t const *pregs, @@ -118,3 +121,21 @@ void sve_restore_state(struct vcpu *v) sve_load_ctx(sve_ctx_zreg_end, v->arch.vfp.fpregs, 1); } + +int __init sve_sanitize_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 and not bigger than the maximum value + * 2048 + */ + if ( val < 0 ) + *out = get_sys_vl_len(); + else if ( ((val % SVE_VL_MULTIPLE_VAL) == 0) && (val <= SVE_VL_MAX_BITS) ) + *out = val; + else + return -1; + + return 0; +} diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c index eeb4662f0eee..3f30ef5c37b6 100644 --- a/xen/arch/arm/domain_build.c +++ b/xen/arch/arm/domain_build.c @@ -26,6 +26,7 @@ #include <asm/platform.h> #include <asm/psci.h> #include <asm/setup.h> +#include <asm/arm64/sve.h> #include <asm/cpufeature.h> #include <asm/domain_build.h> #include <xen/event.h> @@ -61,6 +62,21 @@ 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); +#else + no_config_param("ARM64_SVE", "sve", s, e); +#endif + return 0; + } + return -EINVAL; } @@ -4109,6 +4125,17 @@ void __init create_dom0(void) if ( iommu_enabled ) dom0_cfg.flags |= XEN_DOMCTL_CDF_iommu; + if ( opt_dom0_sve ) + { + unsigned int vl; + + if ( !sve_sanitize_vl_param(opt_dom0_sve, &vl) ) + dom0_cfg.arch.sve_vl = sve_encode_vl(vl); + else + printk(XENLOG_WARNING + "SVE vector length error, disable feature for Dom0\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 fc162c9d2cf7..f1801876b5de 100644 --- a/xen/arch/arm/include/asm/arm64/sve.h +++ b/xen/arch/arm/include/asm/arm64/sve.h @@ -19,8 +19,15 @@ 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; +} + #ifdef CONFIG_ARM64_SVE +extern int opt_dom0_sve; + register_t compute_max_zcr(void); register_t vl_to_zcr(unsigned int vl); unsigned int get_sys_vl_len(void); @@ -28,9 +35,12 @@ 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); +int sve_sanitize_vl_param(int val, unsigned int *out); #else /* !CONFIG_ARM64_SVE */ +#define opt_dom0_sve (0) + static inline register_t compute_max_zcr(void) { return 0; @@ -55,6 +65,11 @@ static inline void sve_context_free(struct vcpu *v) {} static inline void sve_save_state(struct vcpu *v) {} static inline void sve_restore_state(struct vcpu *v) {} +static inline int sve_sanitize_vl_param(int val, unsigned int *out) +{ + return -1; +} + #endif /* CONFIG_ARM64_SVE */ #endif /* _ARM_ARM64_SVE_H */ diff --git a/xen/common/kernel.c b/xen/common/kernel.c index f7b1f65f373c..29d05282c8bb 100644 --- a/xen/common/kernel.c +++ b/xen/common/kernel.c @@ -314,6 +314,31 @@ 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); + + /* Does s start with name or contains only the name? */ + if ( (slen <= nlen) || strncmp(s, name, nlen) || (s[nlen] != '=') ) + return -1; + + pval = simple_strtoll(&s[nlen + 1], &str, 0); + + /* 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=<integer number> + * 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 -- 2.34.1