Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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>
+49
-41
+49
-41
arch/x86/kvm/svm/svm.c
+49
-41
arch/x86/kvm/svm/svm.c
···
421
421
vcpu->arch.osvw.status |= 1;
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422
}
423
423
424
+
static void svm_init_os_visible_workarounds(void)
425
+
{
426
+
u64 len, status;
427
+
int err;
428
+
429
+
/*
430
+
* Get OS-Visible Workarounds (OSVW) bits.
431
+
*
432
+
* Note that it is possible to have a system with mixed processor
433
+
* revisions and therefore different OSVW bits. If bits are not the same
434
+
* on different processors then choose the worst case (i.e. if erratum
435
+
* is present on one processor and not on another then assume that the
436
+
* erratum is present everywhere).
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+
*
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+
* Note #2! The OSVW MSRs are used to communciate that an erratum is
439
+
* NOT present! Software must assume erratum as present if its bit is
440
+
* set in OSVW_STATUS *or* the bit number exceeds OSVW_ID_LENGTH. If
441
+
* either RDMSR fails, simply zero out the length to treat all errata
442
+
* as being present. Similarly, use the *minimum* length across all
443
+
* CPUs, not the maximum length.
444
+
*
445
+
* If the length is zero, then is KVM already treating all errata as
446
+
* being present and there's nothing left to do.
447
+
*/
448
+
if (!osvw_len)
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+
return;
450
+
451
+
if (!boot_cpu_has(X86_FEATURE_OSVW)) {
452
+
osvw_status = osvw_len = 0;
453
+
return;
454
+
}
455
+
456
+
err = native_read_msr_safe(MSR_AMD64_OSVW_ID_LENGTH, &len);
457
+
if (!err)
458
+
err = native_read_msr_safe(MSR_AMD64_OSVW_STATUS, &status);
459
+
460
+
guard(spinlock)(&osvw_lock);
461
+
462
+
if (err) {
463
+
osvw_status = osvw_len = 0;
464
+
} else {
465
+
if (len < osvw_len)
466
+
osvw_len = len;
467
+
osvw_status |= status;
468
+
osvw_status &= (1ULL << osvw_len) - 1;
469
+
}
470
+
}
471
+
424
472
static bool __kvm_is_svm_supported(void)
425
473
{
426
474
int cpu = smp_processor_id();
···
589
541
__svm_write_tsc_multiplier(SVM_TSC_RATIO_DEFAULT);
590
542
}
591
543
592
-
593
-
/*
594
-
* Get OS-Visible Workarounds (OSVW) bits.
595
-
*
596
-
* Note that it is possible to have a system with mixed processor
597
-
* revisions and therefore different OSVW bits. If bits are not the same
598
-
* on different processors then choose the worst case (i.e. if erratum
599
-
* is present on one processor and not on another then assume that the
600
-
* erratum is present everywhere).
601
-
*
602
-
* Note #2! The OSVW MSRs are used to communciate that an erratum is
603
-
* NOT present! Software must assume erratum as present if its bit is
604
-
* set in OSVW_STATUS *or* the bit number exceeds OSVW_ID_LENGTH. If
605
-
* either RDMSR fails, simply zero out the length to treat all errata
606
-
* as being present. Similarly, use the *minimum* length across all
607
-
* CPUs, not the maximum length.
608
-
*
609
-
* If the length is zero, then is KVM already treating all errata as
610
-
* being present and there's nothing left to do.
611
-
*/
612
-
if (osvw_len && cpu_has(&boot_cpu_data, X86_FEATURE_OSVW)) {
613
-
u64 len, status = 0;
614
-
int err;
615
-
616
-
err = native_read_msr_safe(MSR_AMD64_OSVW_ID_LENGTH, &len);
617
-
if (!err)
618
-
err = native_read_msr_safe(MSR_AMD64_OSVW_STATUS, &status);
619
-
620
-
guard(spinlock)(&osvw_lock);
621
-
622
-
if (err) {
623
-
osvw_status = osvw_len = 0;
624
-
} else {
625
-
if (len < osvw_len)
626
-
osvw_len = len;
627
-
osvw_status |= status;
628
-
osvw_status &= (1ULL << osvw_len) - 1;
629
-
}
630
-
} else {
631
-
osvw_status = osvw_len = 0;
632
-
}
544
+
svm_init_os_visible_workarounds();
633
545
634
546
svm_init_erratum_383();
635
547