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KVM: s390: Fix storage attributes migration with memory slots

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This is a fix for several issues that were found in the original code
for storage attributes migration.

Now no bitmap is allocated to keep track of dirty storage attributes;
the extra bits of the per-memslot bitmap that are always present anyway
are now used for this purpose.

The code has also been refactored a little to improve readability.

Fixes: 190df4a212 ("KVM: s390: CMMA tracking, ESSA emulation, migration mode")
Fixes: 4036e3874a ("KVM: s390: ioctls to get and set guest storage attributes")
Acked-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>
Message-Id: <1525106005-13931-3-git-send-email-imbrenda@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This commit is contained in:
Claudio Imbrenda
2018-04-30 18:33:25 +02:00
committed by Christian Borntraeger
parent 03133347b4
commit afdad61615
3 changed files with 197 additions and 137 deletions
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28
arch/s390/kvm/priv.c
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@@ -987,9 +987,11 @@ static int handle_pfmf(struct kvm_vcpu *vcpu)
return 0;
}
static inline int do_essa(struct kvm_vcpu *vcpu, const int orc)
/*
* Must be called with relevant read locks held (kvm->mm->mmap_sem, kvm->srcu)
*/
static inline int __do_essa(struct kvm_vcpu *vcpu, const int orc)
{
struct kvm_s390_migration_state *ms = vcpu->kvm->arch.migration_state;
int r1, r2, nappended, entries;
unsigned long gfn, hva, res, pgstev, ptev;
unsigned long *cbrlo;
@@ -1039,10 +1041,12 @@ static inline int do_essa(struct kvm_vcpu *vcpu, const int orc)
cbrlo[entries] = gfn << PAGE_SHIFT;
}
if (orc && gfn < ms->bitmap_size) {
/* increment only if we are really flipping the bit to 1 */
if (!test_and_set_bit(gfn, ms->pgste_bitmap))
atomic64_inc(&ms->dirty_pages);
if (orc) {
struct kvm_memory_slot *ms = gfn_to_memslot(vcpu->kvm, gfn);
/* Increment only if we are really flipping the bit */
if (ms && !test_and_set_bit(gfn - ms->base_gfn, kvm_second_dirty_bitmap(ms)))
atomic64_inc(&vcpu->kvm->arch.cmma_dirty_pages);
}
return nappended;
@@ -1071,7 +1075,7 @@ static int handle_essa(struct kvm_vcpu *vcpu)
: ESSA_SET_STABLE_IF_RESIDENT))
return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
if (likely(!vcpu->kvm->arch.migration_state)) {
if (!vcpu->kvm->arch.migration_mode) {
/*
* CMMA is enabled in the KVM settings, but is disabled in
* the SIE block and in the mm_context, and we are not doing
@@ -1099,10 +1103,16 @@ static int handle_essa(struct kvm_vcpu *vcpu)
/* Retry the ESSA instruction */
kvm_s390_retry_instr(vcpu);
} else {
/* Account for the possible extra cbrl entry */
i = do_essa(vcpu, orc);
int srcu_idx;
down_read(&vcpu->kvm->mm->mmap_sem);
srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
i = __do_essa(vcpu, orc);
srcu_read_unlock(&vcpu->kvm->srcu, srcu_idx);
up_read(&vcpu->kvm->mm->mmap_sem);
if (i < 0)
return i;
/* Account for the possible extra cbrl entry */
entries += i;
}
vcpu->arch.sie_block->cbrlo &= PAGE_MASK; /* reset nceo */