On 03/04/17 22:15, kbuild test robot wrote:
tree: https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git master
head: 1f1c45c6f66a586ca420ca02cbd93a35690394f9
commit: f9d9eb7f7a2c7e388861fe1cdb253f63e63555fe [1/3] kvm: arm/arm64: Fix locking for kvm_free_stage2_pgd
config: arm-axm55xx_defconfig (attached as .config)
compiler: arm-linux-gnueabi-gcc (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
git checkout f9d9eb7f7a2c7e388861fe1cdb253f63e63555fe
# save the attached .config to linux build tree
make.cross ARCH=arm
All errors (new ones prefixed by >>):
arch/arm/kvm/mmu.c: In function 'unmap_stage2_range':
arch/arm/kvm/mmu.c:302:14: error: 'S2_PUD_SIZE' undeclared (first use in this function)
if (size > S2_PUD_SIZE)
^~~~~~~~~~~
Thanks kbuild for catching this one !
arch/arm/kvm/mmu.c:302:14: note: each undeclared identifier is reported only once for each function it appears in
vim +/S2_PUD_SIZE +302 arch/arm/kvm/mmu.c
296 pgd = kvm->arch.pgd + stage2_pgd_index(addr);
297 do {
298 /*
299 * If the range is too large, release the kvm->mmu_lock
300 * to prevent starvation and lockup detector warnings.
301 */
> 302 if (size > S2_PUD_SIZE)
303 cond_resched_lock(&kvm->mmu_lock);
304 next = stage2_pgd_addr_end(addr, end);
305 if (!stage2_pgd_none(*pgd))
Marc, Christoffer,
Ah! I didn't test this on arm32. We have two options :
1) Define S2_P{U,M}_SIZE for arm32 in asm/stage2_pgtable.h
or,
2) use the following hunk on top of the patch, which changes the lock
release after we process one PGDIR entry. As for the first time we enter
the loop we haven't done much with the lock held, hence it may make
sense to do it after the first round and we have more work to do.
Let me know what you think
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index db94f3a..582a972 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -295,15 +295,15 @@ static void unmap_stage2_range(struct kvm *kvm, phys_addr_t start, u64 size)
assert_spin_locked(&kvm->mmu_lock);
pgd = kvm->arch.pgd + stage2_pgd_index(addr);
do {
+ next = stage2_pgd_addr_end(addr, end);
+ if (!stage2_pgd_none(*pgd))
+ unmap_stage2_puds(kvm, pgd, addr, next);
/*
* If the range is too large, release the kvm->mmu_lock
* to prevent starvation and lockup detector warnings.
*/
- if (size > S2_PUD_SIZE)
+ if (next != end)
cond_resched_lock(&kvm->mmu_lock);
- next = stage2_pgd_addr_end(addr, end);
- if (!stage2_pgd_none(*pgd))
- unmap_stage2_puds(kvm, pgd, addr, next);
} while (pgd++, addr = next, addr != end);
}
Suzuki
---
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