Re: [PATCH v11 9/9] iommu/tegra241-cmdqv: Limit CMDs for guest owned VINTF
From: Will Deacon <will@kernel.org>
Date: 2024-08-16 13:21:09
Also in:
linux-iommu, linux-tegra, lkml
On Tue, Aug 06, 2024 at 07:11:54PM -0700, Nicolin Chen wrote:
quoted hunk ↗ jump to hunk
When VCMDQs are assigned to a VINTF owned by a guest (HYP_OWN bit unset), only TLB and ATC invalidation commands are supported by the VCMDQ HW. So, add a new helper to scan the input cmd to make sure it is supported when selecting a queue, though this assumes that SMMUv3 driver will only add the same type of commands into an arm_smmu_cmdq_batch as it does today. Note that the guest VM shouldn't have HYP_OWN bit being set regardless of guest kernel driver writing it or not, i.e. the hypervisor running in the host OS should wire this bit to zero when trapping a write access to this VINTF_CONFIG register from a guest kernel. Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Nicolin Chen <redacted> --- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 22 +++++++----- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 3 +- .../iommu/arm/arm-smmu-v3/tegra241-cmdqv.c | 35 ++++++++++++++++++- 3 files changed, 49 insertions(+), 11 deletions(-)diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c index 18d940c65e2c..8ff8e264d5e7 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c@@ -336,12 +336,13 @@ static int arm_smmu_cmdq_build_cmd(u64 *cmd, struct arm_smmu_cmdq_ent *ent) return 0; } -static struct arm_smmu_cmdq *arm_smmu_get_cmdq(struct arm_smmu_device *smmu) +static struct arm_smmu_cmdq *arm_smmu_get_cmdq(struct arm_smmu_device *smmu, + u8 opcode) { struct arm_smmu_cmdq *cmdq = NULL; if (smmu->impl && smmu->impl->get_secondary_cmdq) - cmdq = smmu->impl->get_secondary_cmdq(smmu); + cmdq = smmu->impl->get_secondary_cmdq(smmu, opcode); return cmdq ?: &smmu->cmdq; }@@ -889,7 +890,7 @@ static int __arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu, } return arm_smmu_cmdq_issue_cmdlist( - smmu, arm_smmu_get_cmdq(smmu), cmd, 1, sync); + smmu, arm_smmu_get_cmdq(smmu, ent->opcode), cmd, 1, sync); } static int arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu,@@ -905,10 +906,13 @@ static int arm_smmu_cmdq_issue_cmd_with_sync(struct arm_smmu_device *smmu, } static void arm_smmu_cmdq_batch_init(struct arm_smmu_device *smmu, - struct arm_smmu_cmdq_batch *cmds) + struct arm_smmu_cmdq_batch *cmds, + u8 opcode) { + WARN_ON_ONCE(!opcode);
This seems like a fairly arbitrary warning. Remove it?
+ cmds->num = 0; - cmds->cmdq = arm_smmu_get_cmdq(smmu); + cmds->cmdq = arm_smmu_get_cmdq(smmu, opcode);
If we stashed the opcode here, we could actually just enforce that all commands in the batch are the same type in arm_smmu_cmdq_batch_add(). Would that work better for you or not? Will