[PATCH RFC v15 25/30] virt: gunyah: Enable demand paging
Elliot Berman
quic_eberman at quicinc.com
Fri Dec 15 16:21:06 PST 2023
Tell resource manager to enable demand paging and wire vCPU faults to
provide the backing folio when a guestmemfd is bound to the faulting
access.
Signed-off-by: Elliot Berman <quic_eberman at quicinc.com>
---
drivers/virt/gunyah/guest_memfd.c | 92 +++++++++++++++++++++++++++++++++++++++
drivers/virt/gunyah/gunyah_vcpu.c | 39 ++++++++++++++++-
drivers/virt/gunyah/vm_mgr.c | 17 ++++++++
drivers/virt/gunyah/vm_mgr.h | 3 ++
include/linux/gunyah.h | 2 +
5 files changed, 152 insertions(+), 1 deletion(-)
diff --git a/drivers/virt/gunyah/guest_memfd.c b/drivers/virt/gunyah/guest_memfd.c
index 419ed617bd0b..206ce51c9a7d 100644
--- a/drivers/virt/gunyah/guest_memfd.c
+++ b/drivers/virt/gunyah/guest_memfd.c
@@ -732,3 +732,95 @@ int gunyah_gmem_reclaim_parcel(struct gunyah_vm *ghvm,
up_read(&ghvm->mem_lock);
return 0;
}
+
+int gunyah_gmem_setup_demand_paging(struct gunyah_vm *ghvm)
+{
+ struct gunyah_rm_mem_entry *entries;
+ struct gunyah_gmem_binding *b;
+ unsigned long index = 0;
+ u32 count = 0, i;
+ int ret = 0;
+
+ down_read(&ghvm->mem_lock);
+ mt_for_each(&ghvm->mem_layout, b, index, ULONG_MAX)
+ if (gunyah_guest_mem_is_lend(ghvm, b->flags))
+ count++;
+
+ if (!count)
+ goto out;
+
+ entries = kcalloc(count, sizeof(*entries), GFP_KERNEL);
+ if (!entries) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ index = i = 0;
+ mt_for_each(&ghvm->mem_layout, b, index, ULONG_MAX) {
+ if (!gunyah_guest_mem_is_lend(ghvm, b->flags))
+ continue;
+ entries[i].phys_addr = cpu_to_le64(gunyah_gfn_to_gpa(b->gfn));
+ entries[i].size = cpu_to_le64(b->nr << PAGE_SHIFT);
+ if (++i == count)
+ break;
+ }
+
+ ret = gunyah_rm_vm_set_demand_paging(ghvm->rm, ghvm->vmid, i, entries);
+ kfree(entries);
+out:
+ up_read(&ghvm->mem_lock);
+ return ret;
+}
+
+int gunyah_gmem_demand_page(struct gunyah_vm *ghvm, u64 gpa, bool write)
+{
+ unsigned long gfn = gunyah_gpa_to_gfn(gpa);
+ struct gunyah_gmem_binding *b;
+ struct folio *folio;
+ int ret;
+
+ down_read(&ghvm->mem_lock);
+ b = mtree_load(&ghvm->mem_layout, gfn);
+ if (!b) {
+ up_read(&ghvm->mem_lock);
+ return -ENOENT;
+ }
+
+ if (write && !(b->flags & GUNYAH_MEM_ALLOW_WRITE))
+ return -EPERM;
+
+ folio = gunyah_gmem_get_folio(b->inode, gunyah_gfn_to_off(b, gfn));
+ if (IS_ERR(folio)) {
+ up_read(&ghvm->mem_lock);
+ pr_err_ratelimited(
+ "Failed to obtain memory for guest addr %016llx: %ld\n",
+ gpa, PTR_ERR(folio));
+ return PTR_ERR(folio);
+ }
+
+ if (gunyah_guest_mem_is_lend(ghvm, b->flags) && folio_mapped(folio)) {
+ ret = -EPERM;
+ goto out;
+ }
+
+ gfn = gunyah_off_to_gfn(b, folio_index(folio));
+
+ ret = gunyah_vm_provide_folio(ghvm, folio, gfn,
+ !gunyah_guest_mem_is_lend(ghvm, b->flags),
+ !!(b->flags & GUNYAH_MEM_ALLOW_WRITE));
+ if (ret) {
+ pr_err_ratelimited(
+ "Failed to provide folio for guest addr: %016llx: %d\n",
+ gpa, ret);
+ goto out;
+ }
+
+ if (gunyah_guest_mem_is_lend(ghvm, b->flags))
+ folio_set_private(folio);
+out:
+ folio_unlock(folio);
+ folio_put(folio);
+ up_read(&ghvm->mem_lock);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(gunyah_gmem_demand_page);
diff --git a/drivers/virt/gunyah/gunyah_vcpu.c b/drivers/virt/gunyah/gunyah_vcpu.c
index aa40f5977cbf..1952a1797430 100644
--- a/drivers/virt/gunyah/gunyah_vcpu.c
+++ b/drivers/virt/gunyah/gunyah_vcpu.c
@@ -91,6 +91,29 @@ static irqreturn_t gunyah_vcpu_irq_handler(int irq, void *data)
return IRQ_HANDLED;
}
+static bool gunyah_handle_page_fault(
+ struct gunyah_vcpu *vcpu, u64 state_data[3],
+ const struct gunyah_hypercall_vcpu_run_resp *vcpu_run_resp)
+{
+ int ret = 0;
+ u64 addr = vcpu_run_resp->state_data[0];
+ bool write = !!vcpu_run_resp->state_data[1];
+
+ ret = gunyah_gmem_demand_page(vcpu->ghvm, addr, write);
+ if (ret) {
+ if (ret != -ENOENT)
+ pr_warn_ratelimited(
+ "Failed to provide guest address for: %08llx: %d\n",
+ addr, ret);
+
+ vcpu->vcpu_run->page_fault.resume_action = GUNYAH_VCPU_RESUME_FAULT;
+ vcpu->vcpu_run->page_fault.attempt = ret;
+ vcpu->vcpu_run->page_fault.phys_addr = addr;
+ vcpu->vcpu_run->exit_reason = GUNYAH_VCPU_EXIT_PAGE_FAULT;
+ }
+ return !!ret;
+}
+
static bool
gunyah_handle_mmio(struct gunyah_vcpu *vcpu, u64 state_data[3],
const struct gunyah_hypercall_vcpu_run_resp *vcpu_run_resp)
@@ -103,6 +126,12 @@ gunyah_handle_mmio(struct gunyah_vcpu *vcpu, u64 state_data[3],
if (WARN_ON(len > sizeof(u64)))
len = sizeof(u64);
+ if (!gunyah_gmem_demand_page(vcpu->ghvm, addr,
+ vcpu->vcpu_run->mmio.is_write)) {
+ state_data[1] = GUNYAH_ADDRSPACE_VMMIO_ACTION_RETRY;
+ return true;
+ }
+
if (vcpu_run_resp->state == GUNYAH_VCPU_ADDRSPACE_VMMIO_READ) {
vcpu->vcpu_run->mmio.is_write = 0;
/* Record that we need to give vCPU user's supplied value next gunyah_vcpu_run() */
@@ -120,7 +149,8 @@ gunyah_handle_mmio(struct gunyah_vcpu *vcpu, u64 state_data[3],
vcpu->state = GUNYAH_VCPU_MMIO_WRITE;
}
- vcpu->vcpu_run->mmio.phys_addr = addr;
+ vcpu->vcpu_run->mmio.resume_action = 0;
+ vcpu->mmio_addr = vcpu->vcpu_run->mmio.phys_addr = addr;
vcpu->vcpu_run->mmio.len = len;
vcpu->vcpu_run->exit_reason = GUNYAH_VCPU_EXIT_MMIO;
@@ -144,6 +174,8 @@ static int gunyah_handle_mmio_resume(struct gunyah_vcpu *vcpu, u64 state_data[3]
state_data[1] = GUNYAH_ADDRSPACE_VMMIO_ACTION_FAULT;
break;
case GUNYAH_VCPU_RESUME_RETRY:
+ gunyah_gmem_demand_page(vcpu->ghvm, vcpu->mmio_addr,
+ vcpu->state == GUNYAH_VCPU_MMIO_WRITE);
state_data[1] = GUNYAH_ADDRSPACE_VMMIO_ACTION_RETRY;
break;
default:
@@ -300,6 +332,11 @@ static int gunyah_vcpu_run(struct gunyah_vcpu *vcpu)
&vcpu_run_resp))
goto out;
break;
+ case GUNYAH_VCPU_ADDRSPACE_PAGE_FAULT:
+ if (gunyah_handle_page_fault(vcpu, resume_data,
+ &vcpu_run_resp))
+ goto out;
+ break;
default:
pr_warn_ratelimited(
"Unknown vCPU state: %llx\n",
diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c
index 8f8d962c9f8c..0bb2b6a461a5 100644
--- a/drivers/virt/gunyah/vm_mgr.c
+++ b/drivers/virt/gunyah/vm_mgr.c
@@ -653,6 +653,23 @@ static int gunyah_vm_start(struct gunyah_vm *ghvm)
goto err;
}
+ ret = gunyah_gmem_setup_demand_paging(ghvm);
+ if (ret) {
+ dev_warn(ghvm->parent,
+ "Failed to set up gmem demand paging: %d\n", ret);
+ goto err;
+ }
+
+ ret = gunyah_rm_vm_set_address_layout(
+ ghvm->rm, ghvm->vmid, GUNYAH_RM_RANGE_ID_IMAGE,
+ ghvm->dtb.parcel_start << PAGE_SHIFT,
+ ghvm->dtb.parcel_pages << PAGE_SHIFT);
+ if (ret) {
+ dev_warn(ghvm->parent,
+ "Failed to set location of DTB mem parcel: %d\n", ret);
+ goto err;
+ }
+
ret = gunyah_rm_vm_init(ghvm->rm, ghvm->vmid);
if (ret) {
ghvm->vm_status = GUNYAH_RM_VM_STATUS_INIT_FAILED;
diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h
index 357414e67d72..088ed9c55376 100644
--- a/drivers/virt/gunyah/vm_mgr.h
+++ b/drivers/virt/gunyah/vm_mgr.h
@@ -98,4 +98,7 @@ int gunyah_gmem_reclaim_parcel(struct gunyah_vm *ghvm,
struct gunyah_rm_mem_parcel *parcel, u64 gfn,
u64 nr);
+int gunyah_gmem_setup_demand_paging(struct gunyah_vm *ghvm);
+int gunyah_gmem_demand_page(struct gunyah_vm *ghvm, u64 gpa, bool write);
+
#endif
diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
index ae9be5eef7a9..ed461acb9e1b 100644
--- a/include/linux/gunyah.h
+++ b/include/linux/gunyah.h
@@ -223,6 +223,8 @@ struct gunyah_hypercall_vcpu_run_resp {
GUNYAH_VCPU_ADDRSPACE_VMMIO_READ = 4,
/* VCPU has returned for MMIO WRITE */
GUNYAH_VCPU_ADDRSPACE_VMMIO_WRITE = 5,
+ /* Host needs to satisfy a page fault */
+ GUNYAH_VCPU_ADDRSPACE_PAGE_FAULT = 7,
/* clang-format on */
} state;
u64 sized_state;
--
2.43.0
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