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KVM: arm64: Provide the host_stage2_try() helper macro

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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.

Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210809152448.1810400-4-qperret@google.com
This commit is contained in:
Quentin Perret 2021-08-09 16:24:30 +01:00 committed by Marc Zyngier
parent 8e049e0daf
commit 1bac49d490
1 changed files with 22 additions and 18 deletions
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40
arch/arm64/kvm/hyp/nvhe/mem_protect.c
View file

@ -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.
*/
#define host_stage2_try(fn, ...) \
({ \
int __ret; \
hyp_assert_lock_held(&host_kvm.lock); \
__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;