mirrors/linux
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-05-04 00:15:49 -04:00
Code Issues Packages Projects Releases Wiki Activity

KVM: arm64: Handle trapping of FEAT_LS64* instructions

Browse Source 
We generally don't expect FEAT_LS64* instructions to trap, unless
they are trapped by a guest hypervisor.

Otherwise, this is just the guest playing tricks on us by using
an instruction that isn't advertised, which we handle with a well
deserved UNDEF.

Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Marc Zyngier
2024-07-04 18:58:01 +01:00
parent 4b4af68dd9
commit 2e04378f1a
1 changed files with 56 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

56
arch/arm64/kvm/handle_exit.c
View File

@@ -298,6 +298,61 @@ static int handle_svc(struct kvm_vcpu *vcpu)
return 1;
}
static int handle_other(struct kvm_vcpu *vcpu)
{
bool is_l2 = vcpu_has_nv(vcpu) && !is_hyp_ctxt(vcpu);
u64 hcrx = __vcpu_sys_reg(vcpu, HCRX_EL2);
u64 esr = kvm_vcpu_get_esr(vcpu);
u64 iss = ESR_ELx_ISS(esr);
struct kvm *kvm = vcpu->kvm;
bool allowed, fwd = false;
/*
* We only trap for two reasons:
*
* - the feature is disabled, and the only outcome is to
* generate an UNDEF.
*
* - the feature is enabled, but a NV guest wants to trap the
* feature used by its L2 guest. We forward the exception in
* this case.
*
* What we don't expect is to end-up here if the guest is
* expected be be able to directly use the feature, hence the
* WARN_ON below.
*/
switch (iss) {
case ESR_ELx_ISS_OTHER_ST64BV:
allowed = kvm_has_feat(kvm, ID_AA64ISAR1_EL1, LS64, LS64_V);
if (is_l2)
fwd = !(hcrx & HCRX_EL2_EnASR);
break;
case ESR_ELx_ISS_OTHER_ST64BV0:
allowed = kvm_has_feat(kvm, ID_AA64ISAR1_EL1, LS64, LS64_ACCDATA);
if (is_l2)
fwd = !(hcrx & HCRX_EL2_EnAS0);
break;
case ESR_ELx_ISS_OTHER_LDST64B:
allowed = kvm_has_feat(kvm, ID_AA64ISAR1_EL1, LS64, LS64);
if (is_l2)
fwd = !(hcrx & HCRX_EL2_EnALS);
break;
default:
/* Clearly, we're missing something. */
WARN_ON_ONCE(1);
allowed = false;
}
WARN_ON_ONCE(allowed && !fwd);
if (allowed && fwd)
kvm_inject_nested_sync(vcpu, esr);
else
kvm_inject_undefined(vcpu);
return 1;
}
static exit_handle_fn arm_exit_handlers[] = {
[0 ... ESR_ELx_EC_MAX] = kvm_handle_unknown_ec,
[ESR_ELx_EC_WFx] = kvm_handle_wfx,
@@ -307,6 +362,7 @@ static exit_handle_fn arm_exit_handlers[] = {
[ESR_ELx_EC_CP14_LS] = kvm_handle_cp14_load_store,
[ESR_ELx_EC_CP10_ID] = kvm_handle_cp10_id,
[ESR_ELx_EC_CP14_64] = kvm_handle_cp14_64,
[ESR_ELx_EC_OTHER] = handle_other,
[ESR_ELx_EC_HVC32] = handle_hvc,
[ESR_ELx_EC_SMC32] = handle_smc,
[ESR_ELx_EC_HVC64] = handle_hvc,