[Xen-devel] [PATCH] x86/svm: eliminate unnecessary NR_CPUS-sized arrays

["Jan Beulich" <JBeulich@xxxxxxxxxx>]

Replace them with per-CPU data.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

--- 2010-06-15.orig/xen/arch/x86/hvm/svm/svm.c  2010-06-14 08:49:36.000000000 
+0200
+++ 2010-06-15/xen/arch/x86/hvm/svm/svm.c       2010-07-06 15:09:06.000000000 
+0200
@@ -68,10 +68,10 @@ static struct hvm_function_table svm_fun
 enum handler_return { HNDL_done, HNDL_unhandled, HNDL_exception_raised };
 
 /* va of hardware host save area     */
-static void *hsa[NR_CPUS] __read_mostly;
+static DEFINE_PER_CPU_READ_MOSTLY(void *, hsa);
 
 /* vmcb used for extended host state */
-static void *root_vmcb[NR_CPUS] __read_mostly;
+static DEFINE_PER_CPU_READ_MOSTLY(void *, root_vmcb);
 
 static bool_t amd_erratum383_found __read_mostly;
 
@@ -643,7 +643,7 @@ static void svm_ctxt_switch_from(struct 
     vpmu_save(v);
 
     svm_sync_vmcb(v);
-    svm_vmload(root_vmcb[cpu]);
+    svm_vmload(per_cpu(root_vmcb, cpu));
 
 #ifdef __x86_64__
     /* Resume use of ISTs now that the host TR is reinstated. */
@@ -679,7 +679,7 @@ static void svm_ctxt_switch_to(struct vc
 
     svm_restore_dr(v);
 
-    svm_vmsave(root_vmcb[cpu]);
+    svm_vmsave(per_cpu(root_vmcb, cpu));
     svm_vmload(v->arch.hvm_svm.vmcb);
     vpmu_load(v);
 
@@ -821,18 +821,18 @@ static int svm_do_pmu_interrupt(struct c
 
 static void svm_cpu_dead(unsigned int cpu)
 {
-    free_xenheap_page(hsa[cpu]);
-    hsa[cpu] = NULL;
-    free_vmcb(root_vmcb[cpu]);
-    root_vmcb[cpu] = NULL;
+    free_xenheap_page(per_cpu(hsa, cpu));
+    per_cpu(hsa, cpu) = NULL;
+    free_vmcb(per_cpu(root_vmcb, cpu));
+    per_cpu(root_vmcb, cpu) = NULL;
 }
 
 static int svm_cpu_up_prepare(unsigned int cpu)
 {
-    if ( ((hsa[cpu] == NULL) &&
-          ((hsa[cpu] = alloc_host_save_area()) == NULL)) ||
-         ((root_vmcb[cpu] == NULL) &&
-          ((root_vmcb[cpu] = alloc_vmcb()) == NULL)) )
+    if ( ((per_cpu(hsa, cpu) == NULL) &&
+          ((per_cpu(hsa, cpu) = alloc_host_save_area()) == NULL)) ||
+         ((per_cpu(root_vmcb, cpu) == NULL) &&
+          ((per_cpu(root_vmcb, cpu) = alloc_vmcb()) == NULL)) )
     {
         svm_cpu_dead(cpu);
         return -ENOMEM;
@@ -880,7 +880,7 @@ static int svm_cpu_up(void)
     write_efer(read_efer() | EFER_SVME);
 
     /* Initialize the HSA for this core. */
-    wrmsrl(MSR_K8_VM_HSAVE_PA, (uint64_t)virt_to_maddr(hsa[cpu]));
+    wrmsrl(MSR_K8_VM_HSAVE_PA, (uint64_t)virt_to_maddr(per_cpu(hsa, cpu)));
 
     /* check for erratum 383 */
     svm_init_erratum_383(c);

Attachment: svm-no-NR_CPUS.patch
Description: Text document

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