github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-27 16:44:58 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

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

Browse Source 
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>
This commit is contained in:
Sean Christopherson 2025-11-13 15:14:18 -08:00
parent 089af84641
commit c65106af83
1 changed files with 49 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

90
arch/x86/kvm/svm/svm.c
View File

@ -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();