[10/24] KVM: arm/arm64: Release kvm->mmu_lock in loop to prevent starvation

Commit Message

Marc Zyngier May 29, 2020, 4:01 p.m. UTC

From: Jiang Yi <[e-mail]>

Do cond_resched_lock() in stage2_flush_memslot() like what is done in
unmap_stage2_range() and other places holding mmu_lock while processing
a possibly large range of memory.

Signed-off-by: Jiang Yi <[e-mail]>
Signed-off-by: Marc Zyngier <[e-mail]>
Reviewed-by: Suzuki K Poulose <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
---
 arch/arm64/kvm/mmu.c | 3 +++
 1 file changed, 3 insertions(+)

Patch

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 29d8f24df944..917363375e8a 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -422,6 +422,9 @@  static void stage2_flush_memslot(struct kvm *kvm,
 		next = stage2_pgd_addr_end(kvm, addr, end);
 		if (!stage2_pgd_none(kvm, *pgd))
 			stage2_flush_puds(kvm, pgd, addr, next);
+
+		if (next != end)
+			cond_resched_lock(&kvm->mmu_lock);
 	} while (pgd++, addr = next, addr != end);
 }