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BACKPORT: FROMLIST: iommu/arm-smmu-v3-kvm: Probe power domains

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Try to use SCMI if possible, otherwise rely on HVC to the hypervisor
to notify about power changes, this is ONLY safe if the SMMU resets
to blocking DMA.

Link: https://lore.kernel.org/all/20241212180423.1578358-54-smostafa@google.com/

Bug: 357781595
Bug: 384432312

Change-Id: Ie0cf4a53052514849b06b60235c520da966026a9
Signed-off-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
This commit is contained in:
Jean-Philippe Brucker
2024-12-12 18:04:17 +00:00
committed by Mostafa Saleh
parent 94c64f1771
commit 2717852bd5
1 changed files with 78 additions and 0 deletions
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drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
+78
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@@ -8,6 +8,7 @@
#include <asm/kvm_mmu.h>
#include <linux/arm-smccc.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
@@ -21,6 +22,7 @@ struct host_arm_smmu_device {
struct arm_smmu_device smmu;
pkvm_handle_t id;
u32 boot_gbpa;
struct kvm_power_domain power_domain;
};
#define smmu_to_host(_smmu) \
@@ -654,6 +656,77 @@ static int kvm_arm_smmu_device_reset(struct host_arm_smmu_device *host_smmu)
return 0;
}
static int kvm_arm_probe_scmi_pd(struct device_node *scmi_node,
struct kvm_power_domain *pd)
{
int ret;
struct resource res;
struct of_phandle_args args;
pd->type = KVM_POWER_DOMAIN_ARM_SCMI;
ret = of_parse_phandle_with_args(scmi_node, "shmem", NULL, 0, &args);
if (ret)
return ret;
ret = of_address_to_resource(args.np, 0, &res);
if (ret)
goto out_put_nodes;
ret = of_property_read_u32(scmi_node, "arm,smc-id",
&pd->arm_scmi.smc_id);
if (ret)
goto out_put_nodes;
/*
* The shared buffer is unmapped from the host while a request is in
* flight, so it has to be on its own page.
*/
if (!IS_ALIGNED(res.start, SZ_64K) || resource_size(&res) < SZ_64K) {
ret = -EINVAL;
goto out_put_nodes;
}
pd->arm_scmi.shmem_base = res.start;
pd->arm_scmi.shmem_size = resource_size(&res);
out_put_nodes:
of_node_put(args.np);
return ret;
}
/* TODO: Move this. None of it is specific to SMMU */
static int kvm_arm_probe_power_domain(struct device *dev,
struct kvm_power_domain *pd)
{
int ret;
struct device_node *parent;
struct of_phandle_args args;
if (!of_get_property(dev->of_node, "power-domains", NULL))
return 0;
ret = of_parse_phandle_with_args(dev->of_node, "power-domains",
"#power-domain-cells", 0, &args);
if (ret)
return ret;
parent = of_get_parent(args.np);
if (parent && of_device_is_compatible(parent, "arm,scmi-smc") &&
args.args_count > 0) {
pd->arm_scmi.domain_id = args.args[0];
ret = kvm_arm_probe_scmi_pd(parent, pd);
} else {
dev_warn(dev, "Unknown PM method for %pOF, using HVC\n",
args.np);
pd->type = KVM_POWER_DOMAIN_HOST_HVC;
pd->device_id = kvm_arm_smmu_cur;
}
of_node_put(parent);
of_node_put(args.np);
return ret;
}
static int kvm_arm_smmu_probe(struct platform_device *pdev)
{
int ret;
@@ -681,6 +754,10 @@ static int kvm_arm_smmu_probe(struct platform_device *pdev)
if (ret)
return ret;
ret = kvm_arm_probe_power_domain(dev, &host_smmu->power_domain);
if (ret)
return ret;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
size = resource_size(res);
if (size < SZ_128K) {
@@ -738,6 +815,7 @@ static int kvm_arm_smmu_probe(struct platform_device *pdev)
hyp_smmu->mmio_addr = ioaddr;
hyp_smmu->mmio_size = size;
hyp_smmu->features = smmu->features;
hyp_smmu->iommu.power_domain = host_smmu->power_domain;
kvm_arm_smmu_cur++;
return arm_smmu_register_iommu(smmu, &kvm_arm_smmu_ops, ioaddr);