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ANDROID: KVM: arm64: Add hyp request SPLIT

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This request asks the host to split its order 9 kvm_pinned_page. Once
done it also issues a host_split_guest HVC. This intends to be used on
the back of a guest relinquish memory when a stage-2 block mapping is
hit.

Bug: 419548963
Bug: 278011447
Change-Id: I64b18131b42a09c8f34127a1db802753a5aae8b5
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
This commit is contained in:
Vincent Donnefort
2025-05-22 18:15:11 +01:00
parent e56d181356
commit 7c95a219c0
7 changed files with 193 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
android/abi_gki_aarch64.stg
View File

@@ -42943,8 +42943,8 @@ member {
offset: 704
}
member {
id: 0x335fcb96
type_id: 0x42514dcd
id: 0x335fcf90
type_id: 0x42515dd6
offset: 64
}
member {
@@ -189320,6 +189320,11 @@ member {
type_id: 0x0f07cf2c
offset: 1408
}
member {
id: 0x406e59a2
name: "split"
type_id: 0x3721bb90
}
member {
id: 0x406ecc6d
name: "split"
@@ -224306,12 +224311,13 @@ struct_union {
}
}
struct_union {
id: 0x42514dcd
id: 0x42515dd6
kind: UNION
definition {
bytesize: 16
member_id: 0x52238160
member_id: 0x8dc1500c
member_id: 0x406e59a2
}
}
struct_union {
@@ -253209,7 +253215,7 @@ struct_union {
definition {
bytesize: 24
member_id: 0x5c7f890c
member_id: 0x335fcb96
member_id: 0x335fcf90
}
}
struct_union {

5
android/abi_gki_aarch64.stg.allowed_breaks
View File

@@ -136,3 +136,8 @@ type 'struct kvm_protected_vm' changed
member 'struct maple_tree pinned_pages' was removed
member 'union { struct rb_root_cached pinned_pages; struct { struct maple_tree __unused; }; union { }; }' was added
type 'struct kvm_hyp_req' changed
member changed from 'union { struct { u8 dest; int nr_pages; int sz_alloc; } mem; struct { unsigned long guest_ipa; size_t size; } map; }' to 'union { struct { u8 dest; int nr_pages; int sz_alloc; } mem; struct { unsigned long guest_ipa; size_t size; } map; struct { unsigned long guest_ipa; size_t size; } split; }'
type changed from 'union { struct { u8 dest; int nr_pages; int sz_alloc; } mem; struct { unsigned long guest_ipa; size_t size; } map; }' to 'union { struct { u8 dest; int nr_pages; int sz_alloc; } mem; struct { unsigned long guest_ipa; size_t size; } map; struct { unsigned long guest_ipa; size_t size; } split; }'
member 'struct { unsigned long guest_ipa; size_t size; } split' was added

12
arch/arm64/include/asm/kvm_host.h
View File

@@ -224,7 +224,10 @@ struct kvm_smccc_features {
};
struct kvm_pinned_page {
struct rb_node node;
union {
struct rb_node node;
struct list_head list_node;
};
struct page *page;
u64 ipa;
u64 __subtree_last;
@@ -538,6 +541,7 @@ struct kvm_hyp_req {
#define KVM_HYP_LAST_REQ 0
#define KVM_HYP_REQ_TYPE_MEM 1
#define KVM_HYP_REQ_TYPE_MAP 2
#define KVM_HYP_REQ_TYPE_SPLIT 3
u8 type;
union {
struct {
@@ -552,6 +556,12 @@ struct kvm_hyp_req {
unsigned long guest_ipa;
size_t size;
} map;
#ifndef __GENKSYMS__
struct {
unsigned long guest_ipa;
size_t size;
} split;
#endif
};
};

1
arch/arm64/include/asm/kvm_mmu.h
View File

@@ -184,6 +184,7 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
int kvm_handle_guest_abort(struct kvm_vcpu *vcpu);
int pkvm_mem_abort_range(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, size_t size);
int __pkvm_pgtable_stage2_split(struct kvm_vcpu *vcpu, phys_addr_t ipa, size_t size);
phys_addr_t kvm_mmu_get_httbr(void);
phys_addr_t kvm_get_idmap_vector(void);

8
arch/arm64/kvm/handle_exit.c
View File

@@ -363,6 +363,11 @@ static int handle_hyp_req_map(struct kvm_vcpu *vcpu,
return pkvm_mem_abort_range(vcpu, req->map.guest_ipa, req->map.size);
}
static int handle_hyp_req_split(struct kvm_vcpu *vcpu, struct kvm_hyp_req *req)
{
return __pkvm_pgtable_stage2_split(vcpu, req->split.guest_ipa, req->split.size);
}
static int handle_hyp_req(struct kvm_vcpu *vcpu)
{
struct kvm_hyp_req *hyp_req = vcpu->arch.hyp_reqs;
@@ -379,6 +384,9 @@ static int handle_hyp_req(struct kvm_vcpu *vcpu)
case KVM_HYP_REQ_TYPE_MAP:
ret = handle_hyp_req_map(vcpu, hyp_req);
break;
case KVM_HYP_REQ_TYPE_SPLIT:
ret = handle_hyp_req_split(vcpu, hyp_req);
break;
default:
pr_warn("Unknown kvm_hyp_req type: %d\n", hyp_req->type);
ret = -EINVAL;

156
arch/arm64/kvm/mmu.c
View File

@@ -1851,6 +1851,162 @@ end:
return err;
}
static int __pkvm_pin_user_pages(struct kvm *kvm, struct kvm_memory_slot *memslot,
u64 gfn, u64 nr_pages, struct page ***__pages)
{
unsigned long hva = gfn_to_hva_memslot_prot(memslot, gfn, NULL);
unsigned int flags = FOLL_HWPOISON | FOLL_LONGTERM | FOLL_WRITE;
struct mm_struct *mm = current->mm;
struct page **pages;
long ret;
int p;
pages = kmalloc_array(nr_pages, sizeof(*pages), GFP_KERNEL);
if (!pages)
return -ENOMEM;
mmap_read_lock(mm);
ret = pin_user_pages(hva, nr_pages, flags, pages);
mmap_read_unlock(mm);
if (ret == -EHWPOISON) {
kvm_send_hwpoison_signal(hva, PAGE_SHIFT);
goto err_free_pages;
} else if (ret == -EFAULT) {
/* Will try MMIO map */
ret = -EREMOTEIO;
goto err_free_pages;
} else if (ret < 0) {
ret = -EFAULT;
goto err_free_pages;
} else if (ret != nr_pages) {
nr_pages = ret;
ret = -EFAULT;
goto err_unpin_pages;
}
/* See PageSwapBacked() in pkvm_mem_abort() */
for (p = 0; p < nr_pages; p++) {
if (!folio_test_swapbacked(page_folio(pages[p]))) {
ret = -EIO;
goto err_unpin_pages;
}
}
*__pages = pages;
return 0;
err_unpin_pages:
unpin_user_pages(pages, nr_pages);
err_free_pages:
kfree(pages);
return ret;
}
/*
* Splitting is only expected on the back of a relinquish guest HVC in the pKVM case, while
* pkvm_pgtable_stage2_split() can be called with dirty logging.
*/
int __pkvm_pgtable_stage2_split(struct kvm_vcpu *vcpu, phys_addr_t ipa, size_t size)
{
struct list_head ppage_prealloc = LIST_HEAD_INIT(ppage_prealloc);
struct kvm_hyp_memcache *hyp_memcache = &vcpu->arch.stage2_mc;
struct kvm_pinned_page *ppage, *tmp;
struct kvm_memory_slot *memslot;
struct kvm *kvm = vcpu->kvm;
int idx, p, ret, nr_pages;
struct page **pages;
kvm_pfn_t pfn;
gfn_t gfn;
if (!IS_ALIGNED(ipa, PMD_SIZE) || size != PMD_SIZE)
return -EINVAL;
if (!hyp_memcache->nr_pages) {
ret = topup_hyp_memcache(hyp_memcache, 1, 0);
if (ret)
return -ENOMEM;
atomic64_add(PAGE_SIZE, &kvm->stat.protected_hyp_mem);
atomic64_add(PAGE_SIZE, &kvm->stat.protected_pgtable_mem);
}
/* We already have 1 pin on the Huge Page */
nr_pages = (size >> PAGE_SHIFT) - 1;
gfn = (ipa >> PAGE_SHIFT) + 1;
/* Pre-allocate kvm_pinned_page before acquiring the mmu_lock */
for (p = 0; p < nr_pages; p++) {
ppage = kzalloc(sizeof(*ppage), GFP_KERNEL_ACCOUNT);
if (!ppage) {
ret = -ENOMEM;
goto free_pinned_pages;
}
list_add(&ppage->list_node, &ppage_prealloc);
}
idx = srcu_read_lock(&vcpu->kvm->srcu);
memslot = gfn_to_memslot(vcpu->kvm, gfn);
ret = __pkvm_pin_user_pages(kvm, memslot, gfn, nr_pages, &pages);
if (ret)
goto unlock_srcu;
write_lock(&kvm->mmu_lock);
ppage = find_ppage(kvm, ipa);
if (!ppage) {
ret = -EPERM;
goto end;
} else if (!ppage->order) {
ret = 0;
goto end;
}
ret = kvm_call_hyp_nvhe(__pkvm_host_split_guest, page_to_pfn(ppage->page),
ipa >> PAGE_SHIFT, size);
if (ret)
goto end;
ppage->order = 0;
ppage->pins = 1;
pfn = page_to_pfn(ppage->page) + 1;
ipa = ipa + PAGE_SIZE;
while (nr_pages--) {
/* Pop a ppage from the pre-allocated list */
ppage = list_first_entry(&ppage_prealloc, struct kvm_pinned_page, list_node);
list_del_init(&ppage->list_node);
ppage->page = pfn_to_page(pfn);
ppage->ipa = ipa;
ppage->order = 0;
ppage->pins = 1;
kvm_pinned_pages_insert(ppage, &kvm->arch.pkvm.pinned_pages);
pfn += 1;
ipa += PAGE_SIZE;
}
end:
write_unlock(&kvm->mmu_lock);
if (ret)
unpin_user_pages(pages, nr_pages);
kfree(pages);
unlock_srcu:
srcu_read_unlock(&vcpu->kvm->srcu, idx);
free_pinned_pages:
/* Free unused pre-allocated kvm_pinned_page */
list_for_each_entry_safe(ppage, tmp, &ppage_prealloc, list_node) {
list_del(&ppage->list_node);
kfree(ppage);
}
return ret;
}
static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
struct kvm_memory_slot *memslot, unsigned long hva,
unsigned long fault_status)

4
arch/arm64/kvm/pkvm.c
View File

@@ -540,10 +540,10 @@ void pkvm_host_reclaim_page(struct kvm *host_kvm, phys_addr_t ipa)
ppage = kvm_pinned_pages_iter_first(&host_kvm->arch.pkvm.pinned_pages,
ipa, ipa + PAGE_SIZE - 1);
if (ppage) {
WARN_ON_ONCE(ppage->pins != 1);
if (ppage->pins)
ppage->pins--;
else
WARN_ON(1);
pins = ppage->pins;
if (!pins)