[S390] kvm: Handle diagnose 0x10 (release pages)

Linux on System z uses a ballooner based on diagnose 0x10. (aka as
collaborative memory management). This patch implements diagnose
0x10 on the guest address space.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

2 files changed, 32 insertions, 1 deletions

diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c
index 9e4c84187cf5..87cedd61be04 100644
--- a/arch/s390/kvm/diag.c
+++ b/arch/s390/kvm/diag.c
@@ -1,7 +1,7 @@
 /*
  * diag.c - handling diagnose instructions
  *
- * Copyright IBM Corp. 2008
+ * Copyright IBM Corp. 2008,2011
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License (version 2 only)
@@ -15,6 +15,34 @@
 #include <linux/kvm_host.h>
 #include "kvm-s390.h"
 
+static int diag_release_pages(struct kvm_vcpu *vcpu)
+{
+        unsigned long start, end;
+        unsigned long prefix  = vcpu->arch.sie_block->prefix;
+
+        start = vcpu->arch.guest_gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
+        end = vcpu->arch.guest_gprs[vcpu->arch.sie_block->ipa & 0xf] + 4096;
+
+        if (start & ~PAGE_MASK || end & ~PAGE_MASK || start > end
+            || start < 2 * PAGE_SIZE)
+                return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
+
+        VCPU_EVENT(vcpu, 5, "diag release pages %lX %lX", start, end);
+        vcpu->stat.diagnose_10++;
+
+        /* we checked for start > end above */
+        if (end < prefix || start >= prefix + 2 * PAGE_SIZE) {
+                gmap_discard(start, end, vcpu->arch.gmap);
+        } else {
+                if (start < prefix)
+                        gmap_discard(start, prefix, vcpu->arch.gmap);
+                if (end >= prefix)
+                        gmap_discard(prefix + 2 * PAGE_SIZE,
+                                     end, vcpu->arch.gmap);
+        }
+        return 0;
+}
+
 static int __diag_time_slice_end(struct kvm_vcpu *vcpu)
 {
         VCPU_EVENT(vcpu, 5, "%s", "diag time slice end");
@@ -57,6 +85,8 @@ int kvm_s390_handle_diag(struct kvm_vcpu *vcpu)
         int code = (vcpu->arch.sie_block->ipb & 0xfff0000) >> 16;
 
         switch (code) {
+        case 0x10:
+                return diag_release_pages(vcpu);
         case 0x44:
                 return __diag_time_slice_end(vcpu);
         case 0x308:
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index dc2b580e27bc..189d6bdcac08 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -69,6 +69,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
         { "instruction_sigp_set_arch", VCPU_STAT(instruction_sigp_arch) },
         { "instruction_sigp_set_prefix", VCPU_STAT(instruction_sigp_prefix) },
         { "instruction_sigp_restart", VCPU_STAT(instruction_sigp_restart) },
+        { "diagnose_10", VCPU_STAT(diagnose_10) },
         { "diagnose_44", VCPU_STAT(diagnose_44) },
         { NULL }
 };