| Message ID | 1538141967-15375-18-git-send-email-Dave.Martin@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: Initial support for SVE guests | expand |
Dave Martin <Dave.Martin@arm.com> writes: > KVM will need to interrogate the set of SVE vector lengths > available on the system. > > This patch exposes the relevant bits to the kernel, along with a > sve_vq_available() helper to check whether a particular vector > length is supported. > > vq_to_bit() and bit_to_vq() are not intended for use outside these > functions, so they are given a __ prefix to warn people not to use > them unless they really know what they are doing. Personally I wouldn't have bothered with the __ but whatever: Reviewed-by: Alex Bennée <alex.bennee@linaro.org> > > Signed-off-by: Dave Martin <Dave.Martin@arm.com> > --- > arch/arm64/include/asm/fpsimd.h | 29 +++++++++++++++++++++++++++++ > arch/arm64/kernel/fpsimd.c | 35 ++++++++--------------------------- > 2 files changed, 37 insertions(+), 27 deletions(-) > > diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h > index df7a143..ad6d2e4 100644 > --- a/arch/arm64/include/asm/fpsimd.h > +++ b/arch/arm64/include/asm/fpsimd.h > @@ -24,10 +24,13 @@ > > #ifndef __ASSEMBLY__ > > +#include <linux/bitmap.h> > #include <linux/build_bug.h> > +#include <linux/bug.h> > #include <linux/cache.h> > #include <linux/init.h> > #include <linux/stddef.h> > +#include <linux/types.h> > > #if defined(__KERNEL__) && defined(CONFIG_COMPAT) > /* Masks for extracting the FPSR and FPCR from the FPSCR */ > @@ -89,6 +92,32 @@ extern u64 read_zcr_features(void); > > extern int __ro_after_init sve_max_vl; > extern int __ro_after_init sve_max_virtualisable_vl; > +/* Set of available vector lengths, as vq_to_bit(vq): */ > +extern __ro_after_init DECLARE_BITMAP(sve_vq_map, SVE_VQ_MAX); > + > +/* > + * Helpers to translate bit indices in sve_vq_map to VQ values (and > + * vice versa). This allows find_next_bit() to be used to find the > + * _maximum_ VQ not exceeding a certain value. > + */ > +static inline unsigned int __vq_to_bit(unsigned int vq) > +{ > + return SVE_VQ_MAX - vq; > +} > + > +static inline unsigned int __bit_to_vq(unsigned int bit) > +{ > + if (WARN_ON(bit >= SVE_VQ_MAX)) > + bit = SVE_VQ_MAX - 1; > + > + return SVE_VQ_MAX - bit; > +} > + > +/* Ensure vq >= SVE_VQ_MIN && vq <= SVE_VQ_MAX before calling this function */ > +static inline bool sve_vq_available(unsigned int vq) > +{ > + return test_bit(__vq_to_bit(vq), sve_vq_map); > +} > > #ifdef CONFIG_ARM64_SVE > > diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c > index 60c5e28..cc5a495 100644 > --- a/arch/arm64/kernel/fpsimd.c > +++ b/arch/arm64/kernel/fpsimd.c > @@ -136,7 +136,7 @@ static int sve_default_vl = -1; > int __ro_after_init sve_max_vl = SVE_VL_MIN; > int __ro_after_init sve_max_virtualisable_vl = SVE_VL_MIN; > /* Set of available vector lengths, as vq_to_bit(vq): */ > -static __ro_after_init DECLARE_BITMAP(sve_vq_map, SVE_VQ_MAX); > +__ro_after_init DECLARE_BITMAP(sve_vq_map, SVE_VQ_MAX); > /* Set of vector lengths present on at least one cpu: */ > static __ro_after_init DECLARE_BITMAP(sve_vq_partial_map, SVE_VQ_MAX); > static void __percpu *efi_sve_state; > @@ -270,25 +270,6 @@ void fpsimd_save(void) > } > > /* > - * Helpers to translate bit indices in sve_vq_map to VQ values (and > - * vice versa). This allows find_next_bit() to be used to find the > - * _maximum_ VQ not exceeding a certain value. > - */ > - > -static unsigned int vq_to_bit(unsigned int vq) > -{ > - return SVE_VQ_MAX - vq; > -} > - > -static unsigned int bit_to_vq(unsigned int bit) > -{ > - if (WARN_ON(bit >= SVE_VQ_MAX)) > - bit = SVE_VQ_MAX - 1; > - > - return SVE_VQ_MAX - bit; > -} > - > -/* > * All vector length selection from userspace comes through here. > * We're on a slow path, so some sanity-checks are included. > * If things go wrong there's a bug somewhere, but try to fall back to a > @@ -309,8 +290,8 @@ static unsigned int find_supported_vector_length(unsigned int vl) > vl = max_vl; > > bit = find_next_bit(sve_vq_map, SVE_VQ_MAX, > - vq_to_bit(sve_vq_from_vl(vl))); > - return sve_vl_from_vq(bit_to_vq(bit)); > + __vq_to_bit(sve_vq_from_vl(vl))); > + return sve_vl_from_vq(__bit_to_vq(bit)); > } > > #ifdef CONFIG_SYSCTL > @@ -651,7 +632,7 @@ static void sve_probe_vqs(DECLARE_BITMAP(map, SVE_VQ_MAX)) > write_sysreg_s(zcr | (vq - 1), SYS_ZCR_EL1); /* self-syncing */ > vl = sve_get_vl(); > vq = sve_vq_from_vl(vl); /* skip intervening lengths */ > - set_bit(vq_to_bit(vq), map); > + set_bit(__vq_to_bit(vq), map); > } > } > > @@ -712,7 +693,7 @@ int sve_verify_vq_map(void) > * Mismatches above sve_max_virtualisable_vl are fine, since > * no guest is allowed to configure ZCR_EL2.LEN to exceed this: > */ > - if (sve_vl_from_vq(bit_to_vq(b)) <= sve_max_virtualisable_vl) { > + if (sve_vl_from_vq(__bit_to_vq(b)) <= sve_max_virtualisable_vl) { > pr_warn("SVE: cpu%d: Unsupported vector length(s) present\n", > smp_processor_id()); > goto error; > @@ -798,8 +779,8 @@ void __init sve_setup(void) > * so sve_vq_map must have at least SVE_VQ_MIN set. > * If something went wrong, at least try to patch it up: > */ > - if (WARN_ON(!test_bit(vq_to_bit(SVE_VQ_MIN), sve_vq_map))) > - set_bit(vq_to_bit(SVE_VQ_MIN), sve_vq_map); > + if (WARN_ON(!test_bit(__vq_to_bit(SVE_VQ_MIN), sve_vq_map))) > + set_bit(__vq_to_bit(SVE_VQ_MIN), sve_vq_map); > > zcr = read_sanitised_ftr_reg(SYS_ZCR_EL1); > sve_max_vl = sve_vl_from_vq((zcr & ZCR_ELx_LEN_MASK) + 1); > @@ -828,7 +809,7 @@ void __init sve_setup(void) > /* No virtualisable VLs? This is architecturally forbidden. */ > sve_max_virtualisable_vl = SVE_VQ_MIN; > else /* b + 1 < SVE_VQ_MAX */ > - sve_max_virtualisable_vl = sve_vl_from_vq(bit_to_vq(b + 1)); > + sve_max_virtualisable_vl = sve_vl_from_vq(__bit_to_vq(b + 1)); > > if (sve_max_virtualisable_vl > sve_max_vl) > sve_max_virtualisable_vl = sve_max_vl; -- Alex Bennée
On Wed, Nov 21, 2018 at 04:16:42PM +0000, Alex Bennée wrote: > > Dave Martin <Dave.Martin@arm.com> writes: > > > KVM will need to interrogate the set of SVE vector lengths > > available on the system. > > > > This patch exposes the relevant bits to the kernel, along with a > > sve_vq_available() helper to check whether a particular vector > > length is supported. > > > > vq_to_bit() and bit_to_vq() are not intended for use outside these > > functions, so they are given a __ prefix to warn people not to use > > them unless they really know what they are doing. > > Personally I wouldn't have bothered with the __ but whatever: > > Reviewed-by: Alex Bennée <alex.bennee@linaro.org> OK, thanks I'll probably keep the __ unless somebody else objects, but if you feel strongly I could get rid of it. Perhaps I simply shouldn't have called attention to it in the commit message ;) Cheers ---Dave > > > > > Signed-off-by: Dave Martin <Dave.Martin@arm.com> > > --- > > arch/arm64/include/asm/fpsimd.h | 29 +++++++++++++++++++++++++++++ > > arch/arm64/kernel/fpsimd.c | 35 ++++++++--------------------------- > > 2 files changed, 37 insertions(+), 27 deletions(-) > > > > diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h > > index df7a143..ad6d2e4 100644 > > --- a/arch/arm64/include/asm/fpsimd.h > > +++ b/arch/arm64/include/asm/fpsimd.h > > @@ -24,10 +24,13 @@ > > > > #ifndef __ASSEMBLY__ > > > > +#include <linux/bitmap.h> > > #include <linux/build_bug.h> > > +#include <linux/bug.h> > > #include <linux/cache.h> > > #include <linux/init.h> > > #include <linux/stddef.h> > > +#include <linux/types.h> > > > > #if defined(__KERNEL__) && defined(CONFIG_COMPAT) > > /* Masks for extracting the FPSR and FPCR from the FPSCR */ > > @@ -89,6 +92,32 @@ extern u64 read_zcr_features(void); > > > > extern int __ro_after_init sve_max_vl; > > extern int __ro_after_init sve_max_virtualisable_vl; > > +/* Set of available vector lengths, as vq_to_bit(vq): */ > > +extern __ro_after_init DECLARE_BITMAP(sve_vq_map, SVE_VQ_MAX); > > + > > +/* > > + * Helpers to translate bit indices in sve_vq_map to VQ values (and > > + * vice versa). This allows find_next_bit() to be used to find the > > + * _maximum_ VQ not exceeding a certain value. > > + */ > > +static inline unsigned int __vq_to_bit(unsigned int vq) > > +{ > > + return SVE_VQ_MAX - vq; > > +} > > + > > +static inline unsigned int __bit_to_vq(unsigned int bit) > > +{ [...]
Dave Martin <Dave.Martin@arm.com> writes: > On Wed, Nov 21, 2018 at 04:16:42PM +0000, Alex Bennée wrote: >> >> Dave Martin <Dave.Martin@arm.com> writes: >> >> > KVM will need to interrogate the set of SVE vector lengths >> > available on the system. >> > >> > This patch exposes the relevant bits to the kernel, along with a >> > sve_vq_available() helper to check whether a particular vector >> > length is supported. >> > >> > vq_to_bit() and bit_to_vq() are not intended for use outside these >> > functions, so they are given a __ prefix to warn people not to use >> > them unless they really know what they are doing. >> >> Personally I wouldn't have bothered with the __ but whatever: >> >> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> > > OK, thanks > > I'll probably keep the __ unless somebody else objects, but if you feel > strongly I could get rid of it. nah - it's just a personal opinion... > Perhaps I simply shouldn't have called attention to it in the commit > message ;) Psychological priming ;-) > > Cheers > ---Dave > >> >> > >> > Signed-off-by: Dave Martin <Dave.Martin@arm.com> >> > --- >> > arch/arm64/include/asm/fpsimd.h | 29 +++++++++++++++++++++++++++++ >> > arch/arm64/kernel/fpsimd.c | 35 ++++++++--------------------------- >> > 2 files changed, 37 insertions(+), 27 deletions(-) >> > >> > diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h >> > index df7a143..ad6d2e4 100644 >> > --- a/arch/arm64/include/asm/fpsimd.h >> > +++ b/arch/arm64/include/asm/fpsimd.h >> > @@ -24,10 +24,13 @@ >> > >> > #ifndef __ASSEMBLY__ >> > >> > +#include <linux/bitmap.h> >> > #include <linux/build_bug.h> >> > +#include <linux/bug.h> >> > #include <linux/cache.h> >> > #include <linux/init.h> >> > #include <linux/stddef.h> >> > +#include <linux/types.h> >> > >> > #if defined(__KERNEL__) && defined(CONFIG_COMPAT) >> > /* Masks for extracting the FPSR and FPCR from the FPSCR */ >> > @@ -89,6 +92,32 @@ extern u64 read_zcr_features(void); >> > >> > extern int __ro_after_init sve_max_vl; >> > extern int __ro_after_init sve_max_virtualisable_vl; >> > +/* Set of available vector lengths, as vq_to_bit(vq): */ >> > +extern __ro_after_init DECLARE_BITMAP(sve_vq_map, SVE_VQ_MAX); >> > + >> > +/* >> > + * Helpers to translate bit indices in sve_vq_map to VQ values (and >> > + * vice versa). This allows find_next_bit() to be used to find the >> > + * _maximum_ VQ not exceeding a certain value. >> > + */ >> > +static inline unsigned int __vq_to_bit(unsigned int vq) >> > +{ >> > + return SVE_VQ_MAX - vq; >> > +} >> > + >> > +static inline unsigned int __bit_to_vq(unsigned int bit) >> > +{ > > [...] -- Alex Bennée
diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index df7a143..ad6d2e4 100644 --- a/arch/arm64/include/asm/fpsimd.h +++ b/arch/arm64/include/asm/fpsimd.h @@ -24,10 +24,13 @@ #ifndef __ASSEMBLY__ +#include <linux/bitmap.h> #include <linux/build_bug.h> +#include <linux/bug.h> #include <linux/cache.h> #include <linux/init.h> #include <linux/stddef.h> +#include <linux/types.h> #if defined(__KERNEL__) && defined(CONFIG_COMPAT) /* Masks for extracting the FPSR and FPCR from the FPSCR */ @@ -89,6 +92,32 @@ extern u64 read_zcr_features(void); extern int __ro_after_init sve_max_vl; extern int __ro_after_init sve_max_virtualisable_vl; +/* Set of available vector lengths, as vq_to_bit(vq): */ +extern __ro_after_init DECLARE_BITMAP(sve_vq_map, SVE_VQ_MAX); + +/* + * Helpers to translate bit indices in sve_vq_map to VQ values (and + * vice versa). This allows find_next_bit() to be used to find the + * _maximum_ VQ not exceeding a certain value. + */ +static inline unsigned int __vq_to_bit(unsigned int vq) +{ + return SVE_VQ_MAX - vq; +} + +static inline unsigned int __bit_to_vq(unsigned int bit) +{ + if (WARN_ON(bit >= SVE_VQ_MAX)) + bit = SVE_VQ_MAX - 1; + + return SVE_VQ_MAX - bit; +} + +/* Ensure vq >= SVE_VQ_MIN && vq <= SVE_VQ_MAX before calling this function */ +static inline bool sve_vq_available(unsigned int vq) +{ + return test_bit(__vq_to_bit(vq), sve_vq_map); +} #ifdef CONFIG_ARM64_SVE diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 60c5e28..cc5a495 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -136,7 +136,7 @@ static int sve_default_vl = -1; int __ro_after_init sve_max_vl = SVE_VL_MIN; int __ro_after_init sve_max_virtualisable_vl = SVE_VL_MIN; /* Set of available vector lengths, as vq_to_bit(vq): */ -static __ro_after_init DECLARE_BITMAP(sve_vq_map, SVE_VQ_MAX); +__ro_after_init DECLARE_BITMAP(sve_vq_map, SVE_VQ_MAX); /* Set of vector lengths present on at least one cpu: */ static __ro_after_init DECLARE_BITMAP(sve_vq_partial_map, SVE_VQ_MAX); static void __percpu *efi_sve_state; @@ -270,25 +270,6 @@ void fpsimd_save(void) } /* - * Helpers to translate bit indices in sve_vq_map to VQ values (and - * vice versa). This allows find_next_bit() to be used to find the - * _maximum_ VQ not exceeding a certain value. - */ - -static unsigned int vq_to_bit(unsigned int vq) -{ - return SVE_VQ_MAX - vq; -} - -static unsigned int bit_to_vq(unsigned int bit) -{ - if (WARN_ON(bit >= SVE_VQ_MAX)) - bit = SVE_VQ_MAX - 1; - - return SVE_VQ_MAX - bit; -} - -/* * All vector length selection from userspace comes through here. * We're on a slow path, so some sanity-checks are included. * If things go wrong there's a bug somewhere, but try to fall back to a @@ -309,8 +290,8 @@ static unsigned int find_supported_vector_length(unsigned int vl) vl = max_vl; bit = find_next_bit(sve_vq_map, SVE_VQ_MAX, - vq_to_bit(sve_vq_from_vl(vl))); - return sve_vl_from_vq(bit_to_vq(bit)); + __vq_to_bit(sve_vq_from_vl(vl))); + return sve_vl_from_vq(__bit_to_vq(bit)); } #ifdef CONFIG_SYSCTL @@ -651,7 +632,7 @@ static void sve_probe_vqs(DECLARE_BITMAP(map, SVE_VQ_MAX)) write_sysreg_s(zcr | (vq - 1), SYS_ZCR_EL1); /* self-syncing */ vl = sve_get_vl(); vq = sve_vq_from_vl(vl); /* skip intervening lengths */ - set_bit(vq_to_bit(vq), map); + set_bit(__vq_to_bit(vq), map); } } @@ -712,7 +693,7 @@ int sve_verify_vq_map(void) * Mismatches above sve_max_virtualisable_vl are fine, since * no guest is allowed to configure ZCR_EL2.LEN to exceed this: */ - if (sve_vl_from_vq(bit_to_vq(b)) <= sve_max_virtualisable_vl) { + if (sve_vl_from_vq(__bit_to_vq(b)) <= sve_max_virtualisable_vl) { pr_warn("SVE: cpu%d: Unsupported vector length(s) present\n", smp_processor_id()); goto error; @@ -798,8 +779,8 @@ void __init sve_setup(void) * so sve_vq_map must have at least SVE_VQ_MIN set. * If something went wrong, at least try to patch it up: */ - if (WARN_ON(!test_bit(vq_to_bit(SVE_VQ_MIN), sve_vq_map))) - set_bit(vq_to_bit(SVE_VQ_MIN), sve_vq_map); + if (WARN_ON(!test_bit(__vq_to_bit(SVE_VQ_MIN), sve_vq_map))) + set_bit(__vq_to_bit(SVE_VQ_MIN), sve_vq_map); zcr = read_sanitised_ftr_reg(SYS_ZCR_EL1); sve_max_vl = sve_vl_from_vq((zcr & ZCR_ELx_LEN_MASK) + 1); @@ -828,7 +809,7 @@ void __init sve_setup(void) /* No virtualisable VLs? This is architecturally forbidden. */ sve_max_virtualisable_vl = SVE_VQ_MIN; else /* b + 1 < SVE_VQ_MAX */ - sve_max_virtualisable_vl = sve_vl_from_vq(bit_to_vq(b + 1)); + sve_max_virtualisable_vl = sve_vl_from_vq(__bit_to_vq(b + 1)); if (sve_max_virtualisable_vl > sve_max_vl) sve_max_virtualisable_vl = sve_max_vl;
KVM will need to interrogate the set of SVE vector lengths available on the system. This patch exposes the relevant bits to the kernel, along with a sve_vq_available() helper to check whether a particular vector length is supported. vq_to_bit() and bit_to_vq() are not intended for use outside these functions, so they are given a __ prefix to warn people not to use them unless they really know what they are doing. Signed-off-by: Dave Martin <Dave.Martin@arm.com> --- arch/arm64/include/asm/fpsimd.h | 29 +++++++++++++++++++++++++++++ arch/arm64/kernel/fpsimd.c | 35 ++++++++--------------------------- 2 files changed, 37 insertions(+), 27 deletions(-)