KVM: PPC: Book3S: Introduce hypervisor call H_GET_TCE

This introduces the H_GET_TCE hypervisor call, which is basically the
reverse of H_PUT_TCE, as defined in the Power Architecture Platform
Requirements (PAPR).

The hcall H_GET_TCE is required by the kdump kernel, which uses it to
retrieve TCEs set up by the previous (panicked) kernel.

Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>

3 files changed, 31 insertions, 1 deletions

diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index fcd53f0d34ba..4096f16502a9 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -129,6 +129,8 @@ extern long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
                                 struct kvm_create_spapr_tce *args);
 extern long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
                              unsigned long ioba, unsigned long tce);
+extern long kvmppc_h_get_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
+                             unsigned long ioba);
 extern struct kvm_rma_info *kvm_alloc_rma(void);
 extern void kvm_release_rma(struct kvm_rma_info *ri);
 extern struct page *kvm_alloc_hpt(unsigned long nr_pages);
diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/book3s_64_vio_hv.c
index 2c25f5412bdb..89e96b3e0039 100644
--- a/arch/powerpc/kvm/book3s_64_vio_hv.c
+++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
@@ -75,3 +75,31 @@ long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
         return H_TOO_HARD;
 }
 EXPORT_SYMBOL_GPL(kvmppc_h_put_tce);
+
+long kvmppc_h_get_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
+                      unsigned long ioba)
+{
+        struct kvm *kvm = vcpu->kvm;
+        struct kvmppc_spapr_tce_table *stt;
+
+        list_for_each_entry(stt, &kvm->arch.spapr_tce_tables, list) {
+                if (stt->liobn == liobn) {
+                        unsigned long idx = ioba >> SPAPR_TCE_SHIFT;
+                        struct page *page;
+                        u64 *tbl;
+
+                        if (ioba >= stt->window_size)
+                                return H_PARAMETER;
+
+                        page = stt->pages[idx / TCES_PER_PAGE];
+                        tbl = (u64 *)page_address(page);
+
+                        vcpu->arch.gpr[4] = tbl[idx % TCES_PER_PAGE];
+                        return H_SUCCESS;
+                }
+        }
+
+        /* Didn't find the liobn, punt it to userspace */
+        return H_TOO_HARD;
+}
+EXPORT_SYMBOL_GPL(kvmppc_h_get_tce);
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 818dce344e82..7c5788c735c9 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -1691,7 +1691,7 @@ hcall_real_table:
         .long   0               /* 0x10 - H_CLEAR_MOD */
         .long   0               /* 0x14 - H_CLEAR_REF */
         .long   .kvmppc_h_protect - hcall_real_table
-        .long   0               /* 0x1c - H_GET_TCE */
+        .long   .kvmppc_h_get_tce - hcall_real_table
         .long   .kvmppc_h_put_tce - hcall_real_table
         .long   0               /* 0x24 - H_SET_SPRG0 */
         .long   .kvmppc_h_set_dabr - hcall_real_table