On Thu, 29 Jul 2021 11:58:39 +0200 Janosch Frank <frankja@xxxxxxxxxxxxx> wrote: > On 7/28/21 4:26 PM, Claudio Imbrenda wrote: > > Improve make_secure_pte to avoid stalls when the system is heavily > > overcommitted. This was especially problematic in > > kvm_s390_pv_unpack, because of the loop over all pages that needed > > unpacking. > > > > Also fix kvm_s390_pv_init_vm to avoid stalls when the system is > > heavily overcommitted. > > Fixes tag? will be in the next version > > > > Signed-off-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx> > > --- > > arch/s390/kernel/uv.c | 11 ++++++++--- > > arch/s390/kvm/pv.c | 2 +- > > 2 files changed, 9 insertions(+), 4 deletions(-) > > > > diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c > > index aeb0a15bcbb7..fd0faa51c1bb 100644 > > --- a/arch/s390/kernel/uv.c > > +++ b/arch/s390/kernel/uv.c > > @@ -196,11 +196,16 @@ static int make_secure_pte(pte_t *ptep, > > unsigned long addr, if (!page_ref_freeze(page, expected)) > > return -EBUSY; > > set_bit(PG_arch_1, &page->flags); > > - rc = uv_call(0, (u64)uvcb); > > + rc = __uv_call(0, (u64)uvcb); > > We should exchange rc with cc since that's what we get back from > __uv_call(). Technically we always get a cc but for the other > functions it's only ever 0/1 which translates to success/error so rc > is ok. will be in the next version > > page_ref_unfreeze(page, expected); > > - /* Return -ENXIO if the page was not mapped, -EINVAL > > otherwise */ > > - if (rc) > > + /* > > + * Return -ENXIO if the page was not mapped, -EINVAL for > > other errors. > > + * If busy or partially completed, return -EAGAIN. > > + */ > > + if (rc == 1) > > rc = uvcb->rc == 0x10a ? -ENXIO : -EINVAL; > > + else if (rc > 1) > > + rc = -EAGAIN; > > return rc; > > Could you define the CCs in uv.h and check against the constants here > so it's easier to understand that the rc > 1 checks against a "UV was > busy please re-issue the call again" cc? > > Maybe also make it explicit for cc 2 and 3 instead of cc > 1 will be in the next version > > } > > > > diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c > > index c8841f476e91..e007df11a2fe 100644 > > --- a/arch/s390/kvm/pv.c > > +++ b/arch/s390/kvm/pv.c > > @@ -196,7 +196,7 @@ int kvm_s390_pv_init_vm(struct kvm *kvm, u16 > > *rc, u16 *rrc) uvcb.conf_base_stor_origin = > > (u64)kvm->arch.pv.stor_base; uvcb.conf_virt_stor_origin = > > (u64)kvm->arch.pv.stor_var; > > - cc = uv_call(0, (u64)&uvcb); > > + cc = uv_call_sched(0, (u64)&uvcb); > > *rc = uvcb.header.rc; > > *rrc = uvcb.header.rrc; > > KVM_UV_EVENT(kvm, 3, "PROTVIRT CREATE VM: handle %llx len > > %llx rc %x rrc %x", >
