| Message ID | 20210816150718.3063877-2-scgl@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: s390: Some gaccess cleanup | expand |
On 8/16/21 5:07 PM, Janis Schoetterl-Glausch wrote: > Introduce a helper function for guest frame access. > Rewrite the calculation of the gpa and the length of the segment > to be more readable. > > Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com> Reviewed-by: Janosch Frank <frankja@linux.ibm.com> > --- > arch/s390/kvm/gaccess.c | 48 +++++++++++++++++++++++++---------------- > 1 file changed, 29 insertions(+), 19 deletions(-) > > diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c > index b9f85b2dc053..df83de0843de 100644 > --- a/arch/s390/kvm/gaccess.c > +++ b/arch/s390/kvm/gaccess.c > @@ -827,11 +827,26 @@ static int guest_page_range(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, > return 0; > } > > +static int access_guest_frame(struct kvm *kvm, enum gacc_mode mode, gpa_t gpa, > + void *data, unsigned int len) > +{ > + gfn_t gfn = gpa_to_gfn(gpa); > + unsigned int offset = offset_in_page(gpa); > + int rc; > + > + if (mode == GACC_STORE) > + rc = kvm_write_guest_page(kvm, gfn, data, offset, len); > + else > + rc = kvm_read_guest_page(kvm, gfn, data, offset, len); > + return rc; > +} > + > int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data, > unsigned long len, enum gacc_mode mode) > { > psw_t *psw = &vcpu->arch.sie_block->gpsw; > - unsigned long _len, nr_pages, gpa, idx; > + unsigned long nr_pages, gpa, idx; > + unsigned int seg; > unsigned long pages_array[2]; > unsigned long *pages; > int need_ipte_lock; > @@ -855,15 +870,12 @@ int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data, > ipte_lock(vcpu); > rc = guest_page_range(vcpu, ga, ar, pages, nr_pages, asce, mode); > for (idx = 0; idx < nr_pages && !rc; idx++) { > - gpa = *(pages + idx) + (ga & ~PAGE_MASK); > - _len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len); > - if (mode == GACC_STORE) > - rc = kvm_write_guest(vcpu->kvm, gpa, data, _len); > - else > - rc = kvm_read_guest(vcpu->kvm, gpa, data, _len); > - len -= _len; > - ga += _len; > - data += _len; > + gpa = pages[idx] + offset_in_page(ga); > + seg = min(PAGE_SIZE - offset_in_page(gpa), len); > + rc = access_guest_frame(vcpu->kvm, mode, gpa, data, seg); > + len -= seg; > + ga += seg; > + data += seg; > } > if (need_ipte_lock) > ipte_unlock(vcpu); > @@ -875,19 +887,17 @@ int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data, > int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, > void *data, unsigned long len, enum gacc_mode mode) > { > - unsigned long _len, gpa; > + unsigned long gpa; > + unsigned int seg; > int rc = 0; > > while (len && !rc) { > gpa = kvm_s390_real_to_abs(vcpu, gra); > - _len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len); > - if (mode) > - rc = write_guest_abs(vcpu, gpa, data, _len); > - else > - rc = read_guest_abs(vcpu, gpa, data, _len); > - len -= _len; > - gra += _len; > - data += _len; > + seg = min(PAGE_SIZE - offset_in_page(gpa), len); > + rc = access_guest_frame(vcpu->kvm, mode, gpa, data, seg); > + len -= seg; > + gra += seg; > + data += seg; > } > return rc; > } >
On 16.08.21 17:07, Janis Schoetterl-Glausch wrote: > Introduce a helper function for guest frame access. > Rewrite the calculation of the gpa and the length of the segment > to be more readable. > > Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com> > --- > arch/s390/kvm/gaccess.c | 48 +++++++++++++++++++++++++---------------- > 1 file changed, 29 insertions(+), 19 deletions(-) > > diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c > index b9f85b2dc053..df83de0843de 100644 > --- a/arch/s390/kvm/gaccess.c > +++ b/arch/s390/kvm/gaccess.c > @@ -827,11 +827,26 @@ static int guest_page_range(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, > return 0; > } > > +static int access_guest_frame(struct kvm *kvm, enum gacc_mode mode, gpa_t gpa, > + void *data, unsigned int len) I know, "frame" is a beautiful term for "page" -- can we just avoid using it because we're not using it anywhere else here? :) What's wrong with "access_guest_page()" ? > +{ > + gfn_t gfn = gpa_to_gfn(gpa); > + unsigned int offset = offset_in_page(gpa); > + int rc; You could turn both const. You might want to consider reverse-christmas-treeing this. > + > + if (mode == GACC_STORE) > + rc = kvm_write_guest_page(kvm, gfn, data, offset, len); > + else > + rc = kvm_read_guest_page(kvm, gfn, data, offset, len); Personally, I prefer passing in pfn + offset instead of a gpa. Also avoids having to convert back and forth. > + return rc; > +} > + > int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data, > unsigned long len, enum gacc_mode mode) > { > psw_t *psw = &vcpu->arch.sie_block->gpsw; > - unsigned long _len, nr_pages, gpa, idx; > + unsigned long nr_pages, gpa, idx; > + unsigned int seg; Dito, reverse christmas tree might be worth keeping. > unsigned long pages_array[2]; > unsigned long *pages; > int need_ipte_lock; > @@ -855,15 +870,12 @@ int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data, > ipte_lock(vcpu); > rc = guest_page_range(vcpu, ga, ar, pages, nr_pages, asce, mode); > for (idx = 0; idx < nr_pages && !rc; idx++) { > - gpa = *(pages + idx) + (ga & ~PAGE_MASK); > - _len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len); > - if (mode == GACC_STORE) > - rc = kvm_write_guest(vcpu->kvm, gpa, data, _len); > - else > - rc = kvm_read_guest(vcpu->kvm, gpa, data, _len); > - len -= _len; > - ga += _len; > - data += _len; > + gpa = pages[idx] + offset_in_page(ga); > + seg = min(PAGE_SIZE - offset_in_page(gpa), len); > + rc = access_guest_frame(vcpu->kvm, mode, gpa, data, seg); > + len -= seg; > + ga += seg; > + data += seg; > } > if (need_ipte_lock) > ipte_unlock(vcpu); > @@ -875,19 +887,17 @@ int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data, > int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, > void *data, unsigned long len, enum gacc_mode mode) > { > - unsigned long _len, gpa; > + unsigned long gpa; > + unsigned int seg; > int rc = 0; > > while (len && !rc) { > gpa = kvm_s390_real_to_abs(vcpu, gra); > - _len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len); > - if (mode) > - rc = write_guest_abs(vcpu, gpa, data, _len); > - else > - rc = read_guest_abs(vcpu, gpa, data, _len); > - len -= _len; > - gra += _len; > - data += _len; > + seg = min(PAGE_SIZE - offset_in_page(gpa), len); What does "seg" mean? I certainly know when "len" means -- which is also what the function eats. > + rc = access_guest_frame(vcpu->kvm, mode, gpa, data, seg); > + len -= seg; > + gra += seg; > + data += seg; > } > return rc; > } >
On 8/18/21 9:54 AM, David Hildenbrand wrote: > On 16.08.21 17:07, Janis Schoetterl-Glausch wrote: >> Introduce a helper function for guest frame access. >> Rewrite the calculation of the gpa and the length of the segment >> to be more readable. >> >> Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com> [...] >> - unsigned long _len, gpa; >> + unsigned long gpa; >> + unsigned int seg; >> int rc = 0; >> >> while (len && !rc) { >> gpa = kvm_s390_real_to_abs(vcpu, gra); >> - _len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len); >> - if (mode) >> - rc = write_guest_abs(vcpu, gpa, data, _len); >> - else >> - rc = read_guest_abs(vcpu, gpa, data, _len); >> - len -= _len; >> - gra += _len; >> - data += _len; >> + seg = min(PAGE_SIZE - offset_in_page(gpa), len); > > What does "seg" mean? I certainly know when "len" means -- which is also > what the function eats. What does "_len" mean especially in contrast to "len"? "seg" is used in the common kvm guest access functions so it's at least consistent although I share the sentiment that it's not a great name for the length we access inside the page. Originally I suggested "len_in_page" if you have a better name I'd expect we'll both be happy to discuss it :-) > >> + rc = access_guest_frame(vcpu->kvm, mode, gpa, data, seg); >> + len -= seg; >> + gra += seg; >> + data += seg; >> } >> return rc; >> } >> > >
On 18.08.21 10:06, Janosch Frank wrote: > On 8/18/21 9:54 AM, David Hildenbrand wrote: >> On 16.08.21 17:07, Janis Schoetterl-Glausch wrote: >>> Introduce a helper function for guest frame access. >>> Rewrite the calculation of the gpa and the length of the segment >>> to be more readable. >>> >>> Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com> > [...] >>> - unsigned long _len, gpa; >>> + unsigned long gpa; >>> + unsigned int seg; >>> int rc = 0; >>> >>> while (len && !rc) { >>> gpa = kvm_s390_real_to_abs(vcpu, gra); >>> - _len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len); >>> - if (mode) >>> - rc = write_guest_abs(vcpu, gpa, data, _len); >>> - else >>> - rc = read_guest_abs(vcpu, gpa, data, _len); >>> - len -= _len; >>> - gra += _len; >>> - data += _len; >>> + seg = min(PAGE_SIZE - offset_in_page(gpa), len); >> >> What does "seg" mean? I certainly know when "len" means -- which is also >> what the function eats. > > What does "_len" mean especially in contrast to "len"? > > "seg" is used in the common kvm guest access functions so it's at least > consistent although I share the sentiment that it's not a great name for > the length we access inside the page. > > Originally I suggested "len_in_page" if you have a better name I'd > expect we'll both be happy to discuss it :-) Similar code I encountered in other places uses "len" vs "cur_len" or "total_len" vs. "cur_len". I agree that everything is better than "len" vs. "_len". I just cannot come up with a proper word for "seg" that would make sense. "Segment" ? Maybe my uneducated mind is missing some important English words that just fit perfectly here. Anyhow, just my 2 cents, you maintain this code :)
On 8/18/21 10:44 AM, David Hildenbrand wrote: > On 18.08.21 10:06, Janosch Frank wrote: >> On 8/18/21 9:54 AM, David Hildenbrand wrote: >>> On 16.08.21 17:07, Janis Schoetterl-Glausch wrote: >>>> Introduce a helper function for guest frame access. >>>> Rewrite the calculation of the gpa and the length of the segment >>>> to be more readable. >>>> >>>> Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com> >> [...] >>>> - unsigned long _len, gpa; >>>> + unsigned long gpa; >>>> + unsigned int seg; >>>> int rc = 0; >>>> while (len && !rc) { >>>> gpa = kvm_s390_real_to_abs(vcpu, gra); >>>> - _len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len); >>>> - if (mode) >>>> - rc = write_guest_abs(vcpu, gpa, data, _len); >>>> - else >>>> - rc = read_guest_abs(vcpu, gpa, data, _len); >>>> - len -= _len; >>>> - gra += _len; >>>> - data += _len; >>>> + seg = min(PAGE_SIZE - offset_in_page(gpa), len); >>> >>> What does "seg" mean? I certainly know when "len" means -- which is also >>> what the function eats. >> >> What does "_len" mean especially in contrast to "len"? >> >> "seg" is used in the common kvm guest access functions so it's at least >> consistent although I share the sentiment that it's not a great name for >> the length we access inside the page. >> >> Originally I suggested "len_in_page" if you have a better name I'd >> expect we'll both be happy to discuss it :-) > > Similar code I encountered in other places uses "len" vs "cur_len" or "total_len" vs. "cur_len". I agree that everything is better than "len" vs. "_len". > > I just cannot come up with a proper word for "seg" that would make sense. "Segment" ? Maybe my uneducated mind is missing some important English words that just fit perfectly here. Yes, it's short for segment, kvm_main has a function next_segment to calculate it. I don't like the naming scheme much either. > > Anyhow, just my 2 cents, you maintain this code :) >
On 8/18/21 9:54 AM, David Hildenbrand wrote: > On 16.08.21 17:07, Janis Schoetterl-Glausch wrote: >> Introduce a helper function for guest frame access. >> Rewrite the calculation of the gpa and the length of the segment >> to be more readable. >> >> Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com> >> --- >> arch/s390/kvm/gaccess.c | 48 +++++++++++++++++++++++++---------------- >> 1 file changed, 29 insertions(+), 19 deletions(-) >> >> diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c >> index b9f85b2dc053..df83de0843de 100644 >> --- a/arch/s390/kvm/gaccess.c >> +++ b/arch/s390/kvm/gaccess.c >> @@ -827,11 +827,26 @@ static int guest_page_range(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, >> return 0; >> } >> +static int access_guest_frame(struct kvm *kvm, enum gacc_mode mode, gpa_t gpa, >> + void *data, unsigned int len) > > I know, "frame" is a beautiful term for "page" -- can we just avoid using it because we're not using it anywhere else here? :) > > What's wrong with "access_guest_page()" ? Ok, I'll use page for consistency's sake. > > >> +{ >> + gfn_t gfn = gpa_to_gfn(gpa); >> + unsigned int offset = offset_in_page(gpa); >> + int rc; > > You could turn both const. You might want to consider reverse-christmas-treeing this. Ok > >> + >> + if (mode == GACC_STORE) >> + rc = kvm_write_guest_page(kvm, gfn, data, offset, len); >> + else >> + rc = kvm_read_guest_page(kvm, gfn, data, offset, len); > > Personally, I prefer passing in pfn + offset instead of a gpa. Also avoids having to convert back and forth. In access_guest_real we get back the gpa directly from the translation function. After the next patch the same is true for access_guest. So using gpas everywhere is nicer. And if we were to introduce a len_in_page function the offset would not even show up as an intermediary. > >> + return rc; >> +} >> + >> int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data, >> unsigned long len, enum gacc_mode mode) >> { >> psw_t *psw = &vcpu->arch.sie_block->gpsw; >> - unsigned long _len, nr_pages, gpa, idx; >> + unsigned long nr_pages, gpa, idx; >> + unsigned int seg; > > Dito, reverse christmas tree might be worth keeping. > >> unsigned long pages_array[2]; >> unsigned long *pages; >> int need_ipte_lock; >> @@ -855,15 +870,12 @@ int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data, >> ipte_lock(vcpu); >> rc = guest_page_range(vcpu, ga, ar, pages, nr_pages, asce, mode); >> for (idx = 0; idx < nr_pages && !rc; idx++) { >> - gpa = *(pages + idx) + (ga & ~PAGE_MASK); >> - _len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len); >> - if (mode == GACC_STORE) >> - rc = kvm_write_guest(vcpu->kvm, gpa, data, _len); >> - else >> - rc = kvm_read_guest(vcpu->kvm, gpa, data, _len); >> - len -= _len; >> - ga += _len; >> - data += _len; >> + gpa = pages[idx] + offset_in_page(ga); >> + seg = min(PAGE_SIZE - offset_in_page(gpa), len); >> + rc = access_guest_frame(vcpu->kvm, mode, gpa, data, seg); >> + len -= seg; >> + ga += seg; >> + data += seg; >> } >> if (need_ipte_lock) >> ipte_unlock(vcpu); >> @@ -875,19 +887,17 @@ int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data, >> int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, >> void *data, unsigned long len, enum gacc_mode mode) >> { >> - unsigned long _len, gpa; >> + unsigned long gpa; >> + unsigned int seg; >> int rc = 0; >> while (len && !rc) { >> gpa = kvm_s390_real_to_abs(vcpu, gra); >> - _len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len); >> - if (mode) >> - rc = write_guest_abs(vcpu, gpa, data, _len); >> - else >> - rc = read_guest_abs(vcpu, gpa, data, _len); >> - len -= _len; >> - gra += _len; >> - data += _len; >> + seg = min(PAGE_SIZE - offset_in_page(gpa), len); > > What does "seg" mean? I certainly know when "len" means -- which is also what the function eats. > >> + rc = access_guest_frame(vcpu->kvm, mode, gpa, data, seg); >> + len -= seg; >> + gra += seg; >> + data += seg; >> } >> return rc; >> } >> > >
On 8/18/21 10:06 AM, Janosch Frank wrote: > On 8/18/21 9:54 AM, David Hildenbrand wrote: >> On 16.08.21 17:07, Janis Schoetterl-Glausch wrote: >>> Introduce a helper function for guest frame access. >>> Rewrite the calculation of the gpa and the length of the segment >>> to be more readable. >>> >>> Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com> > [...] >>> - unsigned long _len, gpa; >>> + unsigned long gpa; >>> + unsigned int seg; >>> int rc = 0; >>> >>> while (len && !rc) { >>> gpa = kvm_s390_real_to_abs(vcpu, gra); >>> - _len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len); >>> - if (mode) >>> - rc = write_guest_abs(vcpu, gpa, data, _len); >>> - else >>> - rc = read_guest_abs(vcpu, gpa, data, _len); >>> - len -= _len; >>> - gra += _len; >>> - data += _len; >>> + seg = min(PAGE_SIZE - offset_in_page(gpa), len); >> >> What does "seg" mean? I certainly know when "len" means -- which is also >> what the function eats. > > What does "_len" mean especially in contrast to "len"? > > "seg" is used in the common kvm guest access functions so it's at least > consistent although I share the sentiment that it's not a great name for > the length we access inside the page. > > Originally I suggested "len_in_page" if you have a better name I'd > expect we'll both be happy to discuss it :-) fragment_len ? > >> >>> + rc = access_guest_frame(vcpu->kvm, mode, gpa, data, seg); >>> + len -= seg; >>> + gra += seg; >>> + data += seg; >>> } >>> return rc; >>> } >>> >> >> >
On 8/19/21 3:53 PM, Janis Schoetterl-Glausch wrote: > On 8/18/21 10:06 AM, Janosch Frank wrote: >> On 8/18/21 9:54 AM, David Hildenbrand wrote: >>> On 16.08.21 17:07, Janis Schoetterl-Glausch wrote: >>>> Introduce a helper function for guest frame access. >>>> Rewrite the calculation of the gpa and the length of the segment >>>> to be more readable. >>>> >>>> Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com> >> [...] >>>> - unsigned long _len, gpa; >>>> + unsigned long gpa; >>>> + unsigned int seg; >>>> int rc = 0; >>>> >>>> while (len && !rc) { >>>> gpa = kvm_s390_real_to_abs(vcpu, gra); >>>> - _len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len); >>>> - if (mode) >>>> - rc = write_guest_abs(vcpu, gpa, data, _len); >>>> - else >>>> - rc = read_guest_abs(vcpu, gpa, data, _len); >>>> - len -= _len; >>>> - gra += _len; >>>> - data += _len; >>>> + seg = min(PAGE_SIZE - offset_in_page(gpa), len); >>> >>> What does "seg" mean? I certainly know when "len" means -- which is also >>> what the function eats. >> >> What does "_len" mean especially in contrast to "len"? >> >> "seg" is used in the common kvm guest access functions so it's at least >> consistent although I share the sentiment that it's not a great name for >> the length we access inside the page. >> >> Originally I suggested "len_in_page" if you have a better name I'd >> expect we'll both be happy to discuss it :-) > > fragment_len ? Sounds good to me >> >>> >>>> + rc = access_guest_frame(vcpu->kvm, mode, gpa, data, seg); >>>> + len -= seg; >>>> + gra += seg; >>>> + data += seg; >>>> } >>>> return rc; >>>> } >>>> >>> >>> >> >
diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c index b9f85b2dc053..df83de0843de 100644 --- a/arch/s390/kvm/gaccess.c +++ b/arch/s390/kvm/gaccess.c @@ -827,11 +827,26 @@ static int guest_page_range(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, return 0; } +static int access_guest_frame(struct kvm *kvm, enum gacc_mode mode, gpa_t gpa, + void *data, unsigned int len) +{ + gfn_t gfn = gpa_to_gfn(gpa); + unsigned int offset = offset_in_page(gpa); + int rc; + + if (mode == GACC_STORE) + rc = kvm_write_guest_page(kvm, gfn, data, offset, len); + else + rc = kvm_read_guest_page(kvm, gfn, data, offset, len); + return rc; +} + int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data, unsigned long len, enum gacc_mode mode) { psw_t *psw = &vcpu->arch.sie_block->gpsw; - unsigned long _len, nr_pages, gpa, idx; + unsigned long nr_pages, gpa, idx; + unsigned int seg; unsigned long pages_array[2]; unsigned long *pages; int need_ipte_lock; @@ -855,15 +870,12 @@ int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data, ipte_lock(vcpu); rc = guest_page_range(vcpu, ga, ar, pages, nr_pages, asce, mode); for (idx = 0; idx < nr_pages && !rc; idx++) { - gpa = *(pages + idx) + (ga & ~PAGE_MASK); - _len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len); - if (mode == GACC_STORE) - rc = kvm_write_guest(vcpu->kvm, gpa, data, _len); - else - rc = kvm_read_guest(vcpu->kvm, gpa, data, _len); - len -= _len; - ga += _len; - data += _len; + gpa = pages[idx] + offset_in_page(ga); + seg = min(PAGE_SIZE - offset_in_page(gpa), len); + rc = access_guest_frame(vcpu->kvm, mode, gpa, data, seg); + len -= seg; + ga += seg; + data += seg; } if (need_ipte_lock) ipte_unlock(vcpu); @@ -875,19 +887,17 @@ int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data, int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data, unsigned long len, enum gacc_mode mode) { - unsigned long _len, gpa; + unsigned long gpa; + unsigned int seg; int rc = 0; while (len && !rc) { gpa = kvm_s390_real_to_abs(vcpu, gra); - _len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len); - if (mode) - rc = write_guest_abs(vcpu, gpa, data, _len); - else - rc = read_guest_abs(vcpu, gpa, data, _len); - len -= _len; - gra += _len; - data += _len; + seg = min(PAGE_SIZE - offset_in_page(gpa), len); + rc = access_guest_frame(vcpu->kvm, mode, gpa, data, seg); + len -= seg; + gra += seg; + data += seg; } return rc; }
Introduce a helper function for guest frame access. Rewrite the calculation of the gpa and the length of the segment to be more readable. Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com> --- arch/s390/kvm/gaccess.c | 48 +++++++++++++++++++++++++---------------- 1 file changed, 29 insertions(+), 19 deletions(-)