[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 REPOST 09/12] x86/hvm/ioreq: simplify code and use consistent naming
> -----Original Message----- > From: Roger Pau Monne > Sent: 24 August 2017 18:03 > To: Paul Durrant <Paul.Durrant@xxxxxxxxxx> > Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx; Andrew Cooper > <Andrew.Cooper3@xxxxxxxxxx>; Jan Beulich <jbeulich@xxxxxxxx> > Subject: Re: [Xen-devel] [PATCH v2 REPOST 09/12] x86/hvm/ioreq: simplify > code and use consistent naming > > On Tue, Aug 22, 2017 at 03:51:03PM +0100, Paul Durrant wrote: > > This patch re-works much of the IOREQ server initialization and teardown > > code: > > > > - The hvm_map/unmap_ioreq_gfn() functions are expanded to call > through > > to hvm_alloc/free_ioreq_gfn() rather than expecting them to be called > > separately by outer functions. > > - Several functions now test the validity of the hvm_ioreq_page gfn value > > to determine whether they need to act. This means can be safely called > > for the bufioreq page even when it is not used. > > - hvm_add/remove_ioreq_gfn() simply return in the case of the default > > IOREQ server so callers no longer need to test before calling. > > - hvm_ioreq_server_setup_pages() is renamed to > hvm_ioreq_server_map_pages() > > to mirror the existing hvm_ioreq_server_unmap_pages(). > > > > All of this significantly shortens the code. > > > > Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx> > > --- > > Cc: Jan Beulich <jbeulich@xxxxxxxx> > > Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> > > --- > > xen/arch/x86/hvm/ioreq.c | 181 ++++++++++++++++++---------------------- > ------- > > 1 file changed, 69 insertions(+), 112 deletions(-) > > > > diff --git a/xen/arch/x86/hvm/ioreq.c b/xen/arch/x86/hvm/ioreq.c > > index 5737082238..edfb394c59 100644 > > --- a/xen/arch/x86/hvm/ioreq.c > > +++ b/xen/arch/x86/hvm/ioreq.c > > @@ -181,63 +181,76 @@ bool handle_hvm_io_completion(struct vcpu *v) > > return true; > > } > > > > -static int hvm_alloc_ioreq_gfn(struct domain *d, unsigned long *gfn) > > +static unsigned long hvm_alloc_ioreq_gfn(struct hvm_ioreq_server *s) > > gfn_t as the return type instead? I see that you are moving it, so I > won't insist (I assume there's also some other refactoring involved in > making this return gfn_t). I see there are also further uses of > unsigned long to store gfns, I'm not going to point those out. > > > { > > + struct domain *d = s->domain; > > unsigned int i; > > - int rc; > > > > - rc = -ENOMEM; > > + ASSERT(!s->is_default); > > + > > for ( i = 0; i < sizeof(d->arch.hvm_domain.ioreq_gfn.mask) * 8; i++ ) > > { > > if ( test_and_clear_bit(i, &d->arch.hvm_domain.ioreq_gfn.mask) ) > > { > > The braces are not strictly needed anymore, but that's a question of > taste. > > > - *gfn = d->arch.hvm_domain.ioreq_gfn.base + i; > > - rc = 0; > > - break; > > + return d->arch.hvm_domain.ioreq_gfn.base + i; > > } > > } > > > > - return rc; > > + return gfn_x(INVALID_GFN); > > } > > > > -static void hvm_free_ioreq_gfn(struct domain *d, unsigned long gfn) > > +static void hvm_free_ioreq_gfn(struct hvm_ioreq_server *s, > > + unsigned long gfn) > > { > > + struct domain *d = s->domain; > > unsigned int i = gfn - d->arch.hvm_domain.ioreq_gfn.base; > > > > - if ( gfn != gfn_x(INVALID_GFN) ) > > - set_bit(i, &d->arch.hvm_domain.ioreq_gfn.mask); > > + ASSERT(!s->is_default); > > I would maybe add a gfn != gfn_x(INVALID_GFN) in the ASSERT. > > > + > > + set_bit(i, &d->arch.hvm_domain.ioreq_gfn.mask); > > } > > > > -static void hvm_unmap_ioreq_page(struct hvm_ioreq_server *s, bool > buf) > > +static void hvm_unmap_ioreq_gfn(struct hvm_ioreq_server *s, bool buf) > > I'm not sure if you need the buf parameter, it seems in all cases you > want to unmap everything when calling hvm_unmap_ioreq_gfn? (same > applies to hvm_remove_ioreq_gfn and hvm_add_ioreq_gfn) It's really just so map/unmap and add/remove mirror each other. > > > static int hvm_ioreq_server_map_pages(struct hvm_ioreq_server *s, > > - unsigned long ioreq_gfn, > > - unsigned long bufioreq_gfn) > > -{ > > - int rc; > > - > > - rc = hvm_map_ioreq_page(s, false, ioreq_gfn); > > - if ( rc ) > > - return rc; > > - > > - if ( bufioreq_gfn != gfn_x(INVALID_GFN) ) > > - rc = hvm_map_ioreq_page(s, true, bufioreq_gfn); > > - > > - if ( rc ) > > - hvm_unmap_ioreq_page(s, false); > > - > > - return rc; > > -} > > - > > -static int hvm_ioreq_server_setup_pages(struct hvm_ioreq_server *s, > > - bool handle_bufioreq) > > + bool handle_bufioreq) > > { > > - struct domain *d = s->domain; > > - unsigned long ioreq_gfn = gfn_x(INVALID_GFN); > > - unsigned long bufioreq_gfn = gfn_x(INVALID_GFN); > > - int rc; > > - > > - if ( s->is_default ) > > - { > > - /* > > - * The default ioreq server must handle buffered ioreqs, for > > - * backwards compatibility. > > - */ > > - ASSERT(handle_bufioreq); > > - return hvm_ioreq_server_map_pages(s, > > - d->arch.hvm_domain.params[HVM_PARAM_IOREQ_PFN], > > - d->arch.hvm_domain.params[HVM_PARAM_BUFIOREQ_PFN]); > > - } > > + int rc = -ENOMEM; > > No need to set rc, you are just overwriting it in the next line. > Indeed. Thanks, Paul > Roger. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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