[PATCH v2 02/16] KVM: arm64: Provide the host_stage2_try() helper macro
From: Quentin Perret <hidden>
Date: 2021-07-26 09:29:22
Also in:
kvmarm, lkml
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
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 <redacted> --- arch/arm64/kvm/hyp/nvhe/mem_protect.c | 40 +++++++++++++++------------ 1 file changed, 22 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..871149246f5f 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c@@ -208,6 +208,25 @@ 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. + * + * Must be called with host_kvm.lock held. + */ +#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 +242,7 @@ 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 +261,8 @@ 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;
--
2.32.0.432.gabb21c7263-goog
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