From 106ed2cad9f7bd803bd31a18fe7a9219b077bf95 Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc@google.com> Date: Tue, 6 Jun 2023 17:44:49 -0700 Subject: [PATCH] KVM: SVM: WARN, but continue, if misc_cg_set_capacity() fails WARN and continue if misc_cg_set_capacity() fails, as the only scenario in which it can fail is if the specified resource is invalid, which should never happen when CONFIG_KVM_AMD_SEV=y. Deliberately not bailing "fixes" a theoretical bug where KVM would leak the ASID bitmaps on failure, which again can't happen. If the impossible should happen, the end result is effectively the same with respect to SEV and SEV-ES (they are unusable), while continuing on has the advantage of letting KVM load, i.e. userspace can still run non-SEV guests. Reported-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com> Link: https://lore.kernel.org/r/20230607004449.1421131-1-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com> --- arch/x86/kvm/svm/sev.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index d65578d8784d8..07756b7348ae8 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -2216,9 +2216,7 @@ void __init sev_hardware_setup(void) } sev_asid_count = max_sev_asid - min_sev_asid + 1; - if (misc_cg_set_capacity(MISC_CG_RES_SEV, sev_asid_count)) - goto out; - + WARN_ON_ONCE(misc_cg_set_capacity(MISC_CG_RES_SEV, sev_asid_count)); sev_supported = true; /* SEV-ES support requested? */ @@ -2243,9 +2241,7 @@ void __init sev_hardware_setup(void) goto out; sev_es_asid_count = min_sev_asid - 1; - if (misc_cg_set_capacity(MISC_CG_RES_SEV_ES, sev_es_asid_count)) - goto out; - + WARN_ON_ONCE(misc_cg_set_capacity(MISC_CG_RES_SEV_ES, sev_es_asid_count)); sev_es_supported = true; out: -- 2.30.2