On 4/11/2025 7:40 PM, Sean Christopherson wrote:
On Fri, Apr 11, 2025, Sairaj Kodilkar wrote:
On 4/5/2025 1:08 AM, Sean Christopherson wrote:
WARN if KVM attempts to set vCPU affinity when posted interrupts aren't
enabled, as KVM shouldn't try to enable posting when they're unsupported,
and the IOMMU driver darn well should only advertise posting support when
AMD_IOMMU_GUEST_IR_VAPIC() is true.
Note, KVM consumes is_guest_mode only on success.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
drivers/iommu/amd/iommu.c | 13 +++----------
1 file changed, 3 insertions(+), 10 deletions(-)
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index b3a01b7757ee..4f69a37cf143 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -3852,19 +3852,12 @@ static int amd_ir_set_vcpu_affinity(struct irq_data *data, void *vcpu_info)
if (!dev_data || !dev_data->use_vapic)
return -EINVAL;
+ if (WARN_ON_ONCE(!AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir)))
+ return -EINVAL;
+
Hi Sean,
'dev_data->use_vapic' is always zero when AMD IOMMU uses legacy
interrupts i.e. when AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir) is 0.
Hence you can remove this additional check.
Hmm, or move it above? KVM should never call amd_ir_set_vcpu_affinity() if
IRQ posting is unsupported, and that would make this consistent with the end
behavior of amd_iommu_update_ga() and amd_iommu_{de,}activate_guest_mode().
if (WARN_ON_ONCE(!AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir)))
return -EINVAL;
if (ir_data->iommu == NULL)
return -EINVAL;
dev_data = search_dev_data(ir_data->iommu, irte_info->devid);
/* Note:
* This device has never been set up for guest mode.
* we should not modify the IRTE
*/
if (!dev_data || !dev_data->use_vapic)
return -EINVAL;
I'd like to keep the WARN so that someone will notice if KVM screws up.
Yeah makes sense. Lets move it above
Thanks
Sairaj
