KVM: SVM: Extract OS-visible workarounds setup to helper function

Move the initialization of the global OSVW variables to a helper function
so that svm_enable_virtualization_cpu() isn't polluted with a pile of what
is effectively legacy code.

No functional change intended.

Link: https://patch.msgid.link/20251113231420.1695919-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 695cebf8d72415ba9a17957b2bfea7ab580e4f00..7fccb3d72e1862da5968caeb239b229e82eed74b 100644 (file)
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -421,6 +421,54 @@ static void svm_init_osvw(struct kvm_vcpu *vcpu)
                vcpu->arch.osvw.status |= 1;
 }
 
+static void svm_init_os_visible_workarounds(void)
+{
+       u64 len, status;
+       int err;
+
+       /*
+        * Get OS-Visible Workarounds (OSVW) bits.
+        *
+        * Note that it is possible to have a system with mixed processor
+        * revisions and therefore different OSVW bits. If bits are not the same
+        * on different processors then choose the worst case (i.e. if erratum
+        * is present on one processor and not on another then assume that the
+        * erratum is present everywhere).
+        *
+        * Note #2!  The OSVW MSRs are used to communciate that an erratum is
+        * NOT present!  Software must assume erratum as present if its bit is
+        * set in OSVW_STATUS *or* the bit number exceeds OSVW_ID_LENGTH.  If
+        * either RDMSR fails, simply zero out the length to treat all errata
+        * as being present.  Similarly, use the *minimum* length across all
+        * CPUs, not the maximum length.
+        *
+        * If the length is zero, then is KVM already treating all errata as
+        * being present and there's nothing left to do.
+        */
+       if (!osvw_len)
+               return;
+
+       if (!boot_cpu_has(X86_FEATURE_OSVW)) {
+               osvw_status = osvw_len = 0;
+               return;
+       }
+
+       err = native_read_msr_safe(MSR_AMD64_OSVW_ID_LENGTH, &len);
+       if (!err)
+               err = native_read_msr_safe(MSR_AMD64_OSVW_STATUS, &status);
+
+       guard(spinlock)(&osvw_lock);
+
+       if (err) {
+               osvw_status = osvw_len = 0;
+       } else {
+               if (len < osvw_len)
+                       osvw_len = len;
+               osvw_status |= status;
+               osvw_status &= (1ULL << osvw_len) - 1;
+       }
+}
+
 static bool __kvm_is_svm_supported(void)
 {
        int cpu = smp_processor_id();
@@ -541,47 +589,7 @@ static int svm_enable_virtualization_cpu(void)
                __svm_write_tsc_multiplier(SVM_TSC_RATIO_DEFAULT);
        }
 
-
-       /*
-        * Get OS-Visible Workarounds (OSVW) bits.
-        *
-        * Note that it is possible to have a system with mixed processor
-        * revisions and therefore different OSVW bits. If bits are not the same
-        * on different processors then choose the worst case (i.e. if erratum
-        * is present on one processor and not on another then assume that the
-        * erratum is present everywhere).
-        *
-        * Note #2!  The OSVW MSRs are used to communciate that an erratum is
-        * NOT present!  Software must assume erratum as present if its bit is
-        * set in OSVW_STATUS *or* the bit number exceeds OSVW_ID_LENGTH.  If
-        * either RDMSR fails, simply zero out the length to treat all errata
-        * as being present.  Similarly, use the *minimum* length across all
-        * CPUs, not the maximum length.
-        *
-        * If the length is zero, then is KVM already treating all errata as
-        * being present and there's nothing left to do.
-        */
-       if (osvw_len && cpu_has(&boot_cpu_data, X86_FEATURE_OSVW)) {
-               u64 len, status = 0;
-               int err;
-
-               err = native_read_msr_safe(MSR_AMD64_OSVW_ID_LENGTH, &len);
-               if (!err)
-                       err = native_read_msr_safe(MSR_AMD64_OSVW_STATUS, &status);
-
-               guard(spinlock)(&osvw_lock);
-
-               if (err) {
-                       osvw_status = osvw_len = 0;
-               } else {
-                       if (len < osvw_len)
-                               osvw_len = len;
-                       osvw_status |= status;
-                       osvw_status &= (1ULL << osvw_len) - 1;
-               }
-       } else {
-               osvw_status = osvw_len = 0;
-       }
+       svm_init_os_visible_workarounds();
 
        svm_init_erratum_383();