From 815c2a1c432b072c7cb9f9fde69cbf093ecd34b0 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 6 Jun 2023 17:44:49 -0700 Subject: [PATCH] KVM: SVM: WARN, but continue, if misc_cg_set_capacity() fails [ Upstream commit 106ed2cad9f7bd803bd31a18fe7a9219b077bf95 ] 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 Link: https://lore.kernel.org/r/20230607004449.1421131-1-seanjc@google.com Signed-off-by: Sean Christopherson Stable-dep-of: 0aa6b90ef9d7 ("KVM: SVM: Add support for allowing zero SEV ASIDs") Signed-off-by: Sasha Levin --- 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 1fe9257d87b2..0316fdf5040f 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -2214,9 +2214,7 @@ 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? */ @@ -2241,9 +2239,7 @@ 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: