From: Oliver Upton <oliver.upton@linux.dev>
Date: Fri, 25 Oct 2024 18:23:41 +0000 (+0000)
Subject: KVM: arm64: nv: Allow coarse-grained trap combos to use complex traps
X-Git-Tag: v6.13-rc1~97^2~5^2~2^2~12
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=18aeeeb57b93f5038ad9b1bac2102640e786b1d1;p=thirdparty%2Flinux.git

KVM: arm64: nv: Allow coarse-grained trap combos to use complex traps

KVM uses a sanity-check to avoid infinite recursion in trap combinations
that could potentially depend on itself. Narrow the scope of this sanity
check to the exact CGT IDs that correspond w/ trap combos, opening the
door to using 'complex' traps as part of a combination.

Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20241025182354.3364124-7-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---

diff --git a/arch/arm64/kvm/emulate-nested.c b/arch/arm64/kvm/emulate-nested.c
index 05b6435d02a97..da7ab14e036dc 100644
--- a/arch/arm64/kvm/emulate-nested.c
+++ b/arch/arm64/kvm/emulate-nested.c
@@ -2021,7 +2021,8 @@ check_mcb:
 		cgids = coarse_control_combo[id - __MULTIPLE_CONTROL_BITS__];
 
 		for (int i = 0; cgids[i] != __RESERVED__; i++) {
-			if (cgids[i] >= __MULTIPLE_CONTROL_BITS__) {
+			if (cgids[i] >= __MULTIPLE_CONTROL_BITS__ &&
+			    cgids[i] < __COMPLEX_CONDITIONS__) {
 				kvm_err("Recursive MCB %d/%d\n", id, cgids[i]);
 				ret = -EINVAL;
 			}