| Message ID | 20210719104735.3681732-2-qperret@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Track shared pages at EL2 in protected mode | expand |
Hi Quentin, On Mon, Jul 19, 2021 at 11:47 AM Quentin Perret <qperret@google.com> wrote: > > We currently unmap all MMIO mappings from the host stage-2 to recycle > the pages whenever we run out. In order to make this pattern easy to > re-use from other places, factor the logic out into a dedicated macro. > While at it, apply the macro for the kvm_pgtable_stage2_set_owner() > calls. They're currently only called early on and are guaranteed to > succeed, but making them robust to the -ENOMEM case doesn't hurt and > will avoid painful debugging sessions later on. > > Signed-off-by: Quentin Perret <qperret@google.com> > --- > arch/arm64/kvm/hyp/nvhe/mem_protect.c | 38 ++++++++++++++------------- > 1 file changed, 20 insertions(+), 18 deletions(-) > > diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c > index d938ce95d3bd..56f2117c877b 100644 > --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c > +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c > @@ -208,6 +208,23 @@ static inline int __host_stage2_idmap(u64 start, u64 end, > prot, &host_s2_pool); > } > > +/* > + * The pool has been provided with enough pages to cover all of memory with > + * page granularity, but it is difficult to know how much of the MMIO range > + * we will need to cover upfront, so we may need to 'recycle' the pages if we > + * run out. > + */ > +#define host_stage2_try(fn, ...) \ > + ({ \ > + int __ret = fn(__VA_ARGS__); \ > + if (__ret == -ENOMEM) { \ > + __ret = host_stage2_unmap_dev_all(); \ > + if (!__ret) \ > + __ret = fn(__VA_ARGS__); \ > + } \ > + __ret; \ > + }) I think it might be good to document that this macro expects the host_kvm.lock to be held. Thanks, /fuad > static int host_stage2_idmap(u64 addr) > { > enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R | KVM_PGTABLE_PROT_W; > @@ -223,22 +240,7 @@ static int host_stage2_idmap(u64 addr) > if (ret) > goto unlock; > > - ret = __host_stage2_idmap(range.start, range.end, prot); > - if (ret != -ENOMEM) > - goto unlock; > - > - /* > - * The pool has been provided with enough pages to cover all of memory > - * with page granularity, but it is difficult to know how much of the > - * MMIO range we will need to cover upfront, so we may need to 'recycle' > - * the pages if we run out. > - */ > - ret = host_stage2_unmap_dev_all(); > - if (ret) > - goto unlock; > - > - ret = __host_stage2_idmap(range.start, range.end, prot); > - > + ret = host_stage2_try(__host_stage2_idmap, range.start, range.end, prot); > unlock: > hyp_spin_unlock(&host_kvm.lock); > > @@ -257,8 +259,8 @@ int __pkvm_mark_hyp(phys_addr_t start, phys_addr_t end) > return -EINVAL; > > hyp_spin_lock(&host_kvm.lock); > - ret = kvm_pgtable_stage2_set_owner(&host_kvm.pgt, start, end - start, > - &host_s2_pool, pkvm_hyp_id); > + ret = host_stage2_try(kvm_pgtable_stage2_set_owner, &host_kvm.pgt, > + start, end - start, &host_s2_pool, pkvm_hyp_id); > hyp_spin_unlock(&host_kvm.lock); > > return ret != -EAGAIN ? ret : 0; > -- > 2.32.0.402.g57bb445576-goog >
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index d938ce95d3bd..56f2117c877b 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -208,6 +208,23 @@ static inline int __host_stage2_idmap(u64 start, u64 end, prot, &host_s2_pool); } +/* + * The pool has been provided with enough pages to cover all of memory with + * page granularity, but it is difficult to know how much of the MMIO range + * we will need to cover upfront, so we may need to 'recycle' the pages if we + * run out. + */ +#define host_stage2_try(fn, ...) \ + ({ \ + int __ret = fn(__VA_ARGS__); \ + if (__ret == -ENOMEM) { \ + __ret = host_stage2_unmap_dev_all(); \ + if (!__ret) \ + __ret = fn(__VA_ARGS__); \ + } \ + __ret; \ + }) + static int host_stage2_idmap(u64 addr) { enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R | KVM_PGTABLE_PROT_W; @@ -223,22 +240,7 @@ static int host_stage2_idmap(u64 addr) if (ret) goto unlock; - ret = __host_stage2_idmap(range.start, range.end, prot); - if (ret != -ENOMEM) - goto unlock; - - /* - * The pool has been provided with enough pages to cover all of memory - * with page granularity, but it is difficult to know how much of the - * MMIO range we will need to cover upfront, so we may need to 'recycle' - * the pages if we run out. - */ - ret = host_stage2_unmap_dev_all(); - if (ret) - goto unlock; - - ret = __host_stage2_idmap(range.start, range.end, prot); - + ret = host_stage2_try(__host_stage2_idmap, range.start, range.end, prot); unlock: hyp_spin_unlock(&host_kvm.lock); @@ -257,8 +259,8 @@ int __pkvm_mark_hyp(phys_addr_t start, phys_addr_t end) return -EINVAL; hyp_spin_lock(&host_kvm.lock); - ret = kvm_pgtable_stage2_set_owner(&host_kvm.pgt, start, end - start, - &host_s2_pool, pkvm_hyp_id); + ret = host_stage2_try(kvm_pgtable_stage2_set_owner, &host_kvm.pgt, + start, end - start, &host_s2_pool, pkvm_hyp_id); hyp_spin_unlock(&host_kvm.lock); return ret != -EAGAIN ? ret : 0;
We currently unmap all MMIO mappings from the host stage-2 to recycle the pages whenever we run out. In order to make this pattern easy to re-use from other places, factor the logic out into a dedicated macro. While at it, apply the macro for the kvm_pgtable_stage2_set_owner() calls. They're currently only called early on and are guaranteed to succeed, but making them robust to the -ENOMEM case doesn't hurt and will avoid painful debugging sessions later on. Signed-off-by: Quentin Perret <qperret@google.com> --- arch/arm64/kvm/hyp/nvhe/mem_protect.c | 38 ++++++++++++++------------- 1 file changed, 20 insertions(+), 18 deletions(-)