diff options
| author | Carlos López <clopez@suse.de> | 2026-03-11 02:48:28 +0300 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2026-04-09 22:00:23 +0300 |
| commit | 1d353dae3d33bf22fba47a96b627eeb7bfe37be8 (patch) | |
| tree | df35d1a13510e1fae6214ee76aadb9409718229f | |
| parent | f09b7f4af9bb8a0e4f219bb2ed6af25b8baa8be3 (diff) | |
| download | linux-1d353dae3d33bf22fba47a96b627eeb7bfe37be8.tar.xz | |
KVM: SVM: Move lock-protected allocation of SEV ASID into a separate helper
Extract the lock-protected parts of SEV ASID allocation into a new helper
and opportunistically convert it to use guard() when acquiring the mutex.
Preserve the goto even though it's a little odd, as it's there's a fair
amount of subtlety that makes it surprisingly difficult to replicate the
functionality with a loop construct, and arguably using goto yields the
most readable code.
No functional change intended.
Signed-off-by: Carlos López <clopez@suse.de>
[sean: move code to separate helper, rework shortlog+changelog]
Link: https://patch.msgid.link/20260310234829.2608037-21-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
| -rw-r--r-- | arch/x86/kvm/svm/sev.c | 37 |
1 files changed, 23 insertions, 14 deletions
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 4bf7b2c6b148..1567d01ef464 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -237,6 +237,28 @@ static void sev_misc_cg_uncharge(struct kvm_sev_info *sev) misc_cg_uncharge(type, sev->misc_cg, 1); } +static unsigned int sev_alloc_asid(unsigned int min_asid, unsigned int max_asid) +{ + unsigned int asid; + bool retry = true; + + guard(mutex)(&sev_bitmap_lock); + +again: + asid = find_next_zero_bit(sev_asid_bitmap, max_asid + 1, min_asid); + if (asid > max_asid) { + if (retry && __sev_recycle_asids(min_asid, max_asid)) { + retry = false; + goto again; + } + + return asid; + } + + __set_bit(asid, sev_asid_bitmap); + return asid; +} + static int sev_asid_new(struct kvm_sev_info *sev, unsigned long vm_type) { /* @@ -244,7 +266,6 @@ static int sev_asid_new(struct kvm_sev_info *sev, unsigned long vm_type) * SEV-ES-enabled guest can use from 1 to min_sev_asid - 1. */ unsigned int min_asid, max_asid, asid; - bool retry = true; int ret; if (vm_type == KVM_X86_SNP_VM) { @@ -277,24 +298,12 @@ static int sev_asid_new(struct kvm_sev_info *sev, unsigned long vm_type) return ret; } - mutex_lock(&sev_bitmap_lock); - -again: - asid = find_next_zero_bit(sev_asid_bitmap, max_asid + 1, min_asid); + asid = sev_alloc_asid(min_asid, max_asid); if (asid > max_asid) { - if (retry && __sev_recycle_asids(min_asid, max_asid)) { - retry = false; - goto again; - } - mutex_unlock(&sev_bitmap_lock); ret = -EBUSY; goto e_uncharge; } - __set_bit(asid, sev_asid_bitmap); - - mutex_unlock(&sev_bitmap_lock); - sev->asid = asid; return 0; e_uncharge: |