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author | Marc Zyngier <maz@kernel.org> | 2021-05-06 17:20:12 +0300 |
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committer | Marc Zyngier <maz@kernel.org> | 2021-05-15 12:27:59 +0300 |
commit | 26778aaa134a9aefdf5dbaad904054d7be9d656d (patch) | |
tree | fc5788ff8c741e307d83e72deffa646cee28797c /arch/arm64/kvm/hyp/nvhe/hyp-main.c | |
parent | f5e30680616ab09e690b153b7a68ff7dd13e6579 (diff) | |
download | linux-26778aaa134a9aefdf5dbaad904054d7be9d656d.tar.xz |
KVM: arm64: Commit pending PC adjustemnts before returning to userspace
KVM currently updates PC (and the corresponding exception state)
using a two phase approach: first by setting a set of flags,
then by converting these flags into a state update when the vcpu
is about to enter the guest.
However, this creates a disconnect with userspace if the vcpu thread
returns there with any exception/PC flag set. In this case, the exposed
context is wrong, as userspace doesn't have access to these flags
(they aren't architectural). It also means that these flags are
preserved across a reset, which isn't expected.
To solve this problem, force an explicit synchronisation of the
exception state on vcpu exit to userspace. As an optimisation
for nVHE systems, only perform this when there is something pending.
Reported-by: Zenghui Yu <yuzenghui@huawei.com>
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Tested-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org # 5.11
Diffstat (limited to 'arch/arm64/kvm/hyp/nvhe/hyp-main.c')
-rw-r--r-- | arch/arm64/kvm/hyp/nvhe/hyp-main.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c index f36420a80474..1632f001f4ed 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -28,6 +28,13 @@ static void handle___kvm_vcpu_run(struct kvm_cpu_context *host_ctxt) cpu_reg(host_ctxt, 1) = __kvm_vcpu_run(kern_hyp_va(vcpu)); } +static void handle___kvm_adjust_pc(struct kvm_cpu_context *host_ctxt) +{ + DECLARE_REG(struct kvm_vcpu *, vcpu, host_ctxt, 1); + + __kvm_adjust_pc(kern_hyp_va(vcpu)); +} + static void handle___kvm_flush_vm_context(struct kvm_cpu_context *host_ctxt) { __kvm_flush_vm_context(); @@ -170,6 +177,7 @@ typedef void (*hcall_t)(struct kvm_cpu_context *); static const hcall_t host_hcall[] = { HANDLE_FUNC(__kvm_vcpu_run), + HANDLE_FUNC(__kvm_adjust_pc), HANDLE_FUNC(__kvm_flush_vm_context), HANDLE_FUNC(__kvm_tlb_flush_vmid_ipa), HANDLE_FUNC(__kvm_tlb_flush_vmid), |