| Message ID | 20191220195135.20130-4-liuwe@microsoft.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Clean up viridian code | expand |
> -----Original Message----- > From: Wei Liu <wei.liu.xen@gmail.com> On Behalf Of Wei Liu > Sent: 20 December 2019 19:52 > To: Xen Development List <xen-devel@lists.xenproject.org> > Cc: Michael Kelley <mikelley@microsoft.com>; Durrant, Paul > <pdurrant@amazon.com>; Wei Liu <liuwe@microsoft.com>; Paul Durrant > <paul@xen.org>; Jan Beulich <jbeulich@suse.com>; Andrew Cooper > <andrew.cooper3@citrix.com>; Wei Liu <wl@xen.org>; Roger Pau Monné > <roger.pau@citrix.com> > Subject: [PATCH 3/4] x86: provide and use hv_tsc_scale > > The Hyper-V clock source and Xen's own viridian code need the same > functionality. > > Move the function in viridian/time.c to hyperv.h and use it in both > places. > > No functional change. > > Signed-off-by: Wei Liu <liuwe@microsoft.com> Reviewed-by: Paul Durrant <paul@xen.org> > --- > xen/arch/x86/hvm/viridian/time.c | 30 ++-------------------------- > xen/arch/x86/time.c | 7 +------ > xen/include/asm-x86/guest/hyperv.h | 32 ++++++++++++++++++++++++++++-- > 3 files changed, 33 insertions(+), 36 deletions(-) > > diff --git a/xen/arch/x86/hvm/viridian/time.c > b/xen/arch/x86/hvm/viridian/time.c > index 32e79bbcc4..6b2d745f3a 100644 > --- a/xen/arch/x86/hvm/viridian/time.c > +++ b/xen/arch/x86/hvm/viridian/time.c > @@ -13,6 +13,7 @@ > > #include <asm/apic.h> > #include <asm/event.h> > +#include <asm/guest/hyperv.h> > #include <asm/guest/hyperv-tlfs.h> > #include <asm/hvm/support.h> > > @@ -82,33 +83,6 @@ static void update_reference_tsc(const struct domain > *d, bool initialize) > p->tsc_sequence = seq; > } > > -/* > - * The specification says: "The partition reference time is computed > - * by the following formula: > - * > - * ReferenceTime = ((VirtualTsc * TscScale) >> 64) + TscOffset > - * > - * The multiplication is a 64 bit multiplication, which results in a > - * 128 bit number which is then shifted 64 times to the right to obtain > - * the high 64 bits." > - */ > -static uint64_t scale_tsc(uint64_t tsc, uint64_t scale, int64_t offset) > -{ > - uint64_t result; > - > - /* > - * Quadword MUL takes an implicit operand in RAX, and puts the result > - * in RDX:RAX. Because we only want the result of the multiplication > - * after shifting right by 64 bits, we therefore only need the > content > - * of RDX. > - */ > - asm ( "mulq %[scale]" > - : "+a" (tsc), "=d" (result) > - : [scale] "rm" (scale) ); > - > - return result + offset; > -} > - > static uint64_t trc_val(const struct domain *d, int64_t offset) > { > uint64_t tsc, scale; > @@ -116,7 +90,7 @@ static uint64_t trc_val(const struct domain *d, int64_t > offset) > tsc = hvm_get_guest_tsc(pt_global_vcpu_target(d)); > scale = ((10000ul << 32) / d->arch.tsc_khz) << 32; > > - return scale_tsc(tsc, scale, offset); > + return hv_scale_tsc(tsc, scale, offset); > } > > static void time_ref_count_freeze(const struct domain *d) > diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c > index bbcc9b10b8..d21875de9e 100644 > --- a/xen/arch/x86/time.c > +++ b/xen/arch/x86/time.c > @@ -725,12 +725,7 @@ static inline uint64_t read_hyperv_timer(void) > > } while ( tsc_page->tsc_sequence != seq ); > > - /* ret = ((tsc * scale) >> 64) + offset; */ > - asm ( "mul %[scale]; add %[offset], %[ret]" > - : "+a" (tsc), [ret] "=&d" (ret) > - : [scale] "rm" (scale), [offset] "rm" (offset) ); > - > - return ret; > + return hv_scale_tsc(tsc, scale, offset); > } > > static struct platform_timesource __initdata plt_hyperv_timer = > diff --git a/xen/include/asm-x86/guest/hyperv.h b/xen/include/asm- > x86/guest/hyperv.h > index cc21b9abfc..c7a7f32bd5 100644 > --- a/xen/include/asm-x86/guest/hyperv.h > +++ b/xen/include/asm-x86/guest/hyperv.h > @@ -19,10 +19,38 @@ > #ifndef __X86_GUEST_HYPERV_H__ > #define __X86_GUEST_HYPERV_H__ > > -#ifdef CONFIG_HYPERV_GUEST > - > #include <xen/types.h> > > +/* > + * The specification says: "The partition reference time is computed > + * by the following formula: > + * > + * ReferenceTime = ((VirtualTsc * TscScale) >> 64) + TscOffset > + * > + * The multiplication is a 64 bit multiplication, which results in a > + * 128 bit number which is then shifted 64 times to the right to obtain > + * the high 64 bits." > + */ > +static inline uint64_t hv_scale_tsc(uint64_t tsc, uint64_t scale, > + int64_t offset) > +{ > + uint64_t result; > + > + /* > + * Quadword MUL takes an implicit operand in RAX, and puts the result > + * in RDX:RAX. Because we only want the result of the multiplication > + * after shifting right by 64 bits, we therefore only need the > content > + * of RDX. > + */ > + asm ( "mulq %[scale]" > + : "+a" (tsc), "=d" (result) > + : [scale] "rm" (scale) ); > + > + return result + offset; > +} > + > +#ifdef CONFIG_HYPERV_GUEST > + > #include <asm/guest/hypervisor.h> > > struct ms_hyperv_info { > -- > 2.20.1
diff --git a/xen/arch/x86/hvm/viridian/time.c b/xen/arch/x86/hvm/viridian/time.c index 32e79bbcc4..6b2d745f3a 100644 --- a/xen/arch/x86/hvm/viridian/time.c +++ b/xen/arch/x86/hvm/viridian/time.c @@ -13,6 +13,7 @@ #include <asm/apic.h> #include <asm/event.h> +#include <asm/guest/hyperv.h> #include <asm/guest/hyperv-tlfs.h> #include <asm/hvm/support.h> @@ -82,33 +83,6 @@ static void update_reference_tsc(const struct domain *d, bool initialize) p->tsc_sequence = seq; } -/* - * The specification says: "The partition reference time is computed - * by the following formula: - * - * ReferenceTime = ((VirtualTsc * TscScale) >> 64) + TscOffset - * - * The multiplication is a 64 bit multiplication, which results in a - * 128 bit number which is then shifted 64 times to the right to obtain - * the high 64 bits." - */ -static uint64_t scale_tsc(uint64_t tsc, uint64_t scale, int64_t offset) -{ - uint64_t result; - - /* - * Quadword MUL takes an implicit operand in RAX, and puts the result - * in RDX:RAX. Because we only want the result of the multiplication - * after shifting right by 64 bits, we therefore only need the content - * of RDX. - */ - asm ( "mulq %[scale]" - : "+a" (tsc), "=d" (result) - : [scale] "rm" (scale) ); - - return result + offset; -} - static uint64_t trc_val(const struct domain *d, int64_t offset) { uint64_t tsc, scale; @@ -116,7 +90,7 @@ static uint64_t trc_val(const struct domain *d, int64_t offset) tsc = hvm_get_guest_tsc(pt_global_vcpu_target(d)); scale = ((10000ul << 32) / d->arch.tsc_khz) << 32; - return scale_tsc(tsc, scale, offset); + return hv_scale_tsc(tsc, scale, offset); } static void time_ref_count_freeze(const struct domain *d) diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c index bbcc9b10b8..d21875de9e 100644 --- a/xen/arch/x86/time.c +++ b/xen/arch/x86/time.c @@ -725,12 +725,7 @@ static inline uint64_t read_hyperv_timer(void) } while ( tsc_page->tsc_sequence != seq ); - /* ret = ((tsc * scale) >> 64) + offset; */ - asm ( "mul %[scale]; add %[offset], %[ret]" - : "+a" (tsc), [ret] "=&d" (ret) - : [scale] "rm" (scale), [offset] "rm" (offset) ); - - return ret; + return hv_scale_tsc(tsc, scale, offset); } static struct platform_timesource __initdata plt_hyperv_timer = diff --git a/xen/include/asm-x86/guest/hyperv.h b/xen/include/asm-x86/guest/hyperv.h index cc21b9abfc..c7a7f32bd5 100644 --- a/xen/include/asm-x86/guest/hyperv.h +++ b/xen/include/asm-x86/guest/hyperv.h @@ -19,10 +19,38 @@ #ifndef __X86_GUEST_HYPERV_H__ #define __X86_GUEST_HYPERV_H__ -#ifdef CONFIG_HYPERV_GUEST - #include <xen/types.h> +/* + * The specification says: "The partition reference time is computed + * by the following formula: + * + * ReferenceTime = ((VirtualTsc * TscScale) >> 64) + TscOffset + * + * The multiplication is a 64 bit multiplication, which results in a + * 128 bit number which is then shifted 64 times to the right to obtain + * the high 64 bits." + */ +static inline uint64_t hv_scale_tsc(uint64_t tsc, uint64_t scale, + int64_t offset) +{ + uint64_t result; + + /* + * Quadword MUL takes an implicit operand in RAX, and puts the result + * in RDX:RAX. Because we only want the result of the multiplication + * after shifting right by 64 bits, we therefore only need the content + * of RDX. + */ + asm ( "mulq %[scale]" + : "+a" (tsc), "=d" (result) + : [scale] "rm" (scale) ); + + return result + offset; +} + +#ifdef CONFIG_HYPERV_GUEST + #include <asm/guest/hypervisor.h> struct ms_hyperv_info {
The Hyper-V clock source and Xen's own viridian code need the same functionality. Move the function in viridian/time.c to hyperv.h and use it in both places. No functional change. Signed-off-by: Wei Liu <liuwe@microsoft.com> --- xen/arch/x86/hvm/viridian/time.c | 30 ++-------------------------- xen/arch/x86/time.c | 7 +------ xen/include/asm-x86/guest/hyperv.h | 32 ++++++++++++++++++++++++++++-- 3 files changed, 33 insertions(+), 36 deletions(-)