KVM: PPC: Book3S: Invalidate multiple TCEs at once

Invalidating a TCE cache entry for each updated TCE is quite expensive.
This makes use of the new iommu_table_ops::xchg_no_kill()/tce_kill()
callbacks to bring down the time spent in mapping a huge guest DMA window;
roughly 20s to 10s for each guest's 100GB of DMA space.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190829085252.72370-3-aik@ozlabs.ru

diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c
index c4b606f..5834db0 100644 (file)
--- a/arch/powerpc/kvm/book3s_64_vio.c
+++ b/arch/powerpc/kvm/book3s_64_vio.c
@@ -416,7 +416,7 @@ static void kvmppc_clear_tce(struct mm_struct *mm, struct iommu_table *tbl,
        unsigned long hpa = 0;
        enum dma_data_direction dir = DMA_NONE;
 
-       iommu_tce_xchg(mm, tbl, entry, &hpa, &dir);
+       iommu_tce_xchg_no_kill(mm, tbl, entry, &hpa, &dir);
 }
 
 static long kvmppc_tce_iommu_mapped_dec(struct kvm *kvm,
@@ -447,7 +447,8 @@ static long kvmppc_tce_iommu_do_unmap(struct kvm *kvm,
        unsigned long hpa = 0;
        long ret;
 
-       if (WARN_ON_ONCE(iommu_tce_xchg(kvm->mm, tbl, entry, &hpa, &dir)))
+       if (WARN_ON_ONCE(iommu_tce_xchg_no_kill(kvm->mm, tbl, entry, &hpa,
+                                       &dir)))
                return H_TOO_HARD;
 
        if (dir == DMA_NONE)
@@ -455,7 +456,7 @@ static long kvmppc_tce_iommu_do_unmap(struct kvm *kvm,
 
        ret = kvmppc_tce_iommu_mapped_dec(kvm, tbl, entry);
        if (ret != H_SUCCESS)
-               iommu_tce_xchg(kvm->mm, tbl, entry, &hpa, &dir);
+               iommu_tce_xchg_no_kill(kvm->mm, tbl, entry, &hpa, &dir);
 
        return ret;
 }
@@ -501,7 +502,7 @@ long kvmppc_tce_iommu_do_map(struct kvm *kvm, struct iommu_table *tbl,
        if (mm_iommu_mapped_inc(mem))
                return H_TOO_HARD;
 
-       ret = iommu_tce_xchg(kvm->mm, tbl, entry, &hpa, &dir);
+       ret = iommu_tce_xchg_no_kill(kvm->mm, tbl, entry, &hpa, &dir);
        if (WARN_ON_ONCE(ret)) {
                mm_iommu_mapped_dec(mem);
                return H_TOO_HARD;
@@ -579,6 +580,8 @@ long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
                        ret = kvmppc_tce_iommu_map(vcpu->kvm, stt, stit->tbl,
                                        entry, ua, dir);
 
+               iommu_tce_kill(stit->tbl, entry, 1);
+
                if (ret != H_SUCCESS) {
                        kvmppc_clear_tce(vcpu->kvm->mm, stit->tbl, entry);
                        goto unlock_exit;
@@ -656,13 +659,13 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
                 */
                if (get_user(tce, tces + i)) {
                        ret = H_TOO_HARD;
-                       goto unlock_exit;
+                       goto invalidate_exit;
                }
                tce = be64_to_cpu(tce);
 
                if (kvmppc_tce_to_ua(vcpu->kvm, tce, &ua)) {
                        ret = H_PARAMETER;
-                       goto unlock_exit;
+                       goto invalidate_exit;
                }
 
                list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
@@ -673,13 +676,17 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
                        if (ret != H_SUCCESS) {
                                kvmppc_clear_tce(vcpu->kvm->mm, stit->tbl,
                                                entry);
-                               goto unlock_exit;
+                               goto invalidate_exit;
                        }
                }
 
                kvmppc_tce_put(stt, entry + i, tce);
        }
 
+invalidate_exit:
+       list_for_each_entry_lockless(stit, &stt->iommu_tables, next)
+               iommu_tce_kill(stit->tbl, entry, npages);
+
 unlock_exit:
        srcu_read_unlock(&vcpu->kvm->srcu, idx);
 
@@ -718,7 +725,7 @@ long kvmppc_h_stuff_tce(struct kvm_vcpu *vcpu,
                                continue;
 
                        if (ret == H_TOO_HARD)
-                               return ret;
+                               goto invalidate_exit;
 
                        WARN_ON_ONCE(1);
                        kvmppc_clear_tce(vcpu->kvm->mm, stit->tbl, entry);
@@ -728,6 +735,10 @@ long kvmppc_h_stuff_tce(struct kvm_vcpu *vcpu,
        for (i = 0; i < npages; ++i, ioba += (1ULL << stt->page_shift))
                kvmppc_tce_put(stt, ioba >> stt->page_shift, tce_value);
 
-       return H_SUCCESS;
+invalidate_exit:
+       list_for_each_entry_lockless(stit, &stt->iommu_tables, next)
+               iommu_tce_kill(stit->tbl, ioba >> stt->page_shift, npages);
+
+       return ret;
 }
 EXPORT_SYMBOL_GPL(kvmppc_h_stuff_tce);

diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/book3s_64_vio_hv.c
index b4f20f1..ab6eeb8 100644 (file)
--- a/arch/powerpc/kvm/book3s_64_vio_hv.c
+++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
@@ -218,13 +218,14 @@ static long kvmppc_rm_ioba_validate(struct kvmppc_spapr_tce_table *stt,
        return H_SUCCESS;
 }
 
-static long iommu_tce_xchg_rm(struct mm_struct *mm, struct iommu_table *tbl,
+static long iommu_tce_xchg_no_kill_rm(struct mm_struct *mm,
+               struct iommu_table *tbl,
                unsigned long entry, unsigned long *hpa,
                enum dma_data_direction *direction)
 {
        long ret;
 
-       ret = tbl->it_ops->exchange_rm(tbl, entry, hpa, direction);
+       ret = tbl->it_ops->xchg_no_kill(tbl, entry, hpa, direction, true);
 
        if (!ret && ((*direction == DMA_FROM_DEVICE) ||
                                (*direction == DMA_BIDIRECTIONAL))) {
@@ -240,13 +241,20 @@ static long iommu_tce_xchg_rm(struct mm_struct *mm, struct iommu_table *tbl,
        return ret;
 }
 
+extern void iommu_tce_kill_rm(struct iommu_table *tbl,
+               unsigned long entry, unsigned long pages)
+{
+       if (tbl->it_ops->tce_kill)
+               tbl->it_ops->tce_kill(tbl, entry, pages, true);
+}
+
 static void kvmppc_rm_clear_tce(struct kvm *kvm, struct iommu_table *tbl,
                unsigned long entry)
 {
        unsigned long hpa = 0;
        enum dma_data_direction dir = DMA_NONE;
 
-       iommu_tce_xchg_rm(kvm->mm, tbl, entry, &hpa, &dir);
+       iommu_tce_xchg_no_kill_rm(kvm->mm, tbl, entry, &hpa, &dir);
 }
 
 static long kvmppc_rm_tce_iommu_mapped_dec(struct kvm *kvm,
@@ -278,7 +286,7 @@ static long kvmppc_rm_tce_iommu_do_unmap(struct kvm *kvm,
        unsigned long hpa = 0;
        long ret;
 
-       if (iommu_tce_xchg_rm(kvm->mm, tbl, entry, &hpa, &dir))
+       if (iommu_tce_xchg_no_kill_rm(kvm->mm, tbl, entry, &hpa, &dir))
                /*
                 * real mode xchg can fail if struct page crosses
                 * a page boundary
@@ -290,7 +298,7 @@ static long kvmppc_rm_tce_iommu_do_unmap(struct kvm *kvm,
 
        ret = kvmppc_rm_tce_iommu_mapped_dec(kvm, tbl, entry);
        if (ret)
-               iommu_tce_xchg_rm(kvm->mm, tbl, entry, &hpa, &dir);
+               iommu_tce_xchg_no_kill_rm(kvm->mm, tbl, entry, &hpa, &dir);
 
        return ret;
 }
@@ -336,7 +344,7 @@ static long kvmppc_rm_tce_iommu_do_map(struct kvm *kvm, struct iommu_table *tbl,
        if (WARN_ON_ONCE_RM(mm_iommu_mapped_inc(mem)))
                return H_TOO_HARD;
 
-       ret = iommu_tce_xchg_rm(kvm->mm, tbl, entry, &hpa, &dir);
+       ret = iommu_tce_xchg_no_kill_rm(kvm->mm, tbl, entry, &hpa, &dir);
        if (ret) {
                mm_iommu_mapped_dec(mem);
                /*
@@ -417,6 +425,8 @@ long kvmppc_rm_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
                        ret = kvmppc_rm_tce_iommu_map(vcpu->kvm, stt,
                                        stit->tbl, entry, ua, dir);
 
+               iommu_tce_kill_rm(stit->tbl, entry, 1);
+
                if (ret != H_SUCCESS) {
                        kvmppc_rm_clear_tce(vcpu->kvm, stit->tbl, entry);
                        return ret;
@@ -558,7 +568,7 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
                ua = 0;
                if (kvmppc_rm_tce_to_ua(vcpu->kvm, tce, &ua, NULL)) {
                        ret = H_PARAMETER;
-                       goto unlock_exit;
+                       goto invalidate_exit;
                }
 
                list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
@@ -569,13 +579,17 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
                        if (ret != H_SUCCESS) {
                                kvmppc_rm_clear_tce(vcpu->kvm, stit->tbl,
                                                entry);
-                               goto unlock_exit;
+                               goto invalidate_exit;
                        }
                }
 
                kvmppc_rm_tce_put(stt, entry + i, tce);
        }
 
+invalidate_exit:
+       list_for_each_entry_lockless(stit, &stt->iommu_tables, next)
+               iommu_tce_kill_rm(stit->tbl, entry, npages);
+
 unlock_exit:
        if (rmap)
                unlock_rmap(rmap);
@@ -618,7 +632,7 @@ long kvmppc_rm_h_stuff_tce(struct kvm_vcpu *vcpu,
                                continue;
 
                        if (ret == H_TOO_HARD)
-                               return ret;
+                               goto invalidate_exit;
 
                        WARN_ON_ONCE_RM(1);
                        kvmppc_rm_clear_tce(vcpu->kvm, stit->tbl, entry);
@@ -628,7 +642,11 @@ long kvmppc_rm_h_stuff_tce(struct kvm_vcpu *vcpu,
        for (i = 0; i < npages; ++i, ioba += (1ULL << stt->page_shift))
                kvmppc_rm_tce_put(stt, ioba >> stt->page_shift, tce_value);
 
-       return H_SUCCESS;
+invalidate_exit:
+       list_for_each_entry_lockless(stit, &stt->iommu_tables, next)
+               iommu_tce_kill_rm(stit->tbl, ioba >> stt->page_shift, npages);
+
+       return ret;
 }
 
 /* This can be called in either virtual mode or real mode */