tmakin/ack-tegra
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

ANDROID: KVM: arm64: Rework pKVM module fault handler

Browse Source 
pKVM modules can register up to 16 handlers. In preparation for
supporting multiple handlers for the host SMCs, generalize and move over
that support into modules.c.

Bug: 357781595
Bug: 382397533
Change-Id: Iea9dea628dc5b7b75e46c7e581f3e507d039a06b
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
This commit is contained in:
Vincent Donnefort
2024-12-06 17:13:52 +00:00
parent 2bd9a977ca
commit 0a901ecd7f
4 changed files with 73 additions and 55 deletions
Download Patch File Download Diff File Expand all files Collapse all files
arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
-1
View File
@@ -78,7 +78,6 @@ int kvm_host_prepare_stage2(void *pgt_pool_base);
int kvm_guest_prepare_stage2(struct pkvm_hyp_vm *vm, void *pgd);
void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt);
int hyp_register_host_perm_fault_handler(int (*cb)(struct user_pt_regs *regs, u64 esr, u64 addr));
int hyp_pin_shared_mem(void *from, void *to);
void hyp_unpin_shared_mem(void *from, void *to);
int host_stage2_get_leaf(phys_addr_t phys, kvm_pte_t *ptep, s8 *level);
arch/arm64/kvm/hyp/include/nvhe/modules.h
+2
View File
@@ -17,6 +17,7 @@ int __pkvm_init_module(void *module_init);
int __pkvm_register_hcall(unsigned long hfn_hyp_va);
int handle_host_dynamic_hcall(struct user_pt_regs *regs, int id);
void __pkvm_close_module_registration(void);
bool module_handle_host_perm_fault(struct user_pt_regs *regs, u64 esr, u64 addr);
#else
static inline int __pkvm_init_module(void *module_init) { return -EOPNOTSUPP; }
static inline int
@@ -27,4 +28,5 @@ handle_host_dynamic_hcall(struct kvm_cpu_context *host_ctxt, int id)
return HCALL_UNHANDLED;
}
static inline void __pkvm_close_module_registration(void) { }
bool module_handle_host_perm_fault(struct user_pt_regs *regs, u64 esr, u64 addr) { return false; }
#endif
arch/arm64/kvm/hyp/nvhe/mem_protect.c
+12 -53
View File
@@ -792,53 +792,6 @@ static void host_inject_abort(struct kvm_cpu_context *host_ctxt)
write_sysreg_el2(spsr, SYS_SPSR);
}
#define MAX_HOST_FAULT_HANDLERS 16
static int
(*perm_fault_handlers[MAX_HOST_FAULT_HANDLERS])(struct user_pt_regs *regs, u64 esr, u64 addr);
int hyp_register_host_perm_fault_handler(int (*cb)(struct user_pt_regs *regs, u64 esr, u64 addr))
{
static DEFINE_HYP_SPINLOCK(handlers_lock);
int i;
hyp_spin_lock(&handlers_lock);
for (i = 0; i < MAX_HOST_FAULT_HANDLERS; i++) {
if (!perm_fault_handlers[i]) {
WRITE_ONCE(perm_fault_handlers[i], cb);
break;
}
}
hyp_spin_unlock(&handlers_lock);
return i >= MAX_HOST_FAULT_HANDLERS ? -EBUSY : 0;
}
static int handle_host_perm_fault(struct kvm_cpu_context *host_ctxt, u64 esr, u64 addr)
{
int (*cb)(struct user_pt_regs *regs, u64 esr, u64 addr);
bool handled = false;
int i;
for (i = 0; i < MAX_HOST_FAULT_HANDLERS; i++) {
int err;
cb = READ_ONCE(perm_fault_handlers[i]);
if (!cb)
break;
handled = true;
err = cb(&host_ctxt->regs, esr, addr);
if (err)
return err;
}
return handled ? 0 : -EPERM;
}
static bool is_dabt(u64 esr)
{
return ESR_ELx_EC(esr) == ESR_ELx_EC_DABT_LOW;
@@ -848,7 +801,7 @@ void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt)
{
struct kvm_vcpu_fault_info fault;
u64 esr, addr;
int ret = -EPERM;
int ret;
esr = read_sysreg_el2(SYS_ESR);
if (!__get_fault_info(esr, &fault)) {
@@ -868,12 +821,18 @@ void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt)
kvm_iommu_host_dabt_handler(host_ctxt, esr, addr))
goto return_to_host;
/* If not handled, attempt to map the page. */
if (ret == -EPERM)
switch (esr & ESR_ELx_FSC_TYPE) {
case ESR_ELx_FSC_FAULT:
ret = host_stage2_idmap(addr);
if ((esr & ESR_ELx_FSC_TYPE) == ESR_ELx_FSC_PERM)
ret = handle_host_perm_fault(host_ctxt, esr, addr);
break;
case ESR_ELx_FSC_PERM:
ret = module_handle_host_perm_fault(&host_ctxt->regs, esr, addr);
ret = ret ? 0 /* handled */ : -EPERM;
break;
default:
ret = -EPERM;
break;
}
if (ret == -EPERM)
host_inject_abort(host_ctxt);
arch/arm64/kvm/hyp/nvhe/modules.c
+59 -1
View File
@@ -128,6 +128,64 @@ static int __hyp_smp_processor_id(void)
return hyp_smp_processor_id();
}
#define MAX_MOD_HANDLERS 16
enum mod_handler_type {
HOST_FAULT_HANDLER = 0,
NUM_MOD_HANDLER_TYPES,
};
static void *mod_handlers[NUM_MOD_HANDLER_TYPES][MAX_MOD_HANDLERS];
static int mod_handler_register(enum mod_handler_type type, void *handler)
{
int i;
for (i = 0; i < MAX_MOD_HANDLERS; i++) {
if (!cmpxchg64_release(&mod_handlers[type][i], handler, NULL))
return 0;
}
return -EBUSY;
}
static void *__get_mod_handler(enum mod_handler_type type, int i)
{
if (WARN_ON(type >= NUM_MOD_HANDLER_TYPES))
return NULL;
if (i >= MAX_MOD_HANDLERS)
return NULL;
i = array_index_nospec(i, MAX_MOD_HANDLERS);
return smp_load_acquire(&mod_handlers[type][i]);
}
#define for_each_mod_handler(type, handler, i) \
for ((i) = 0, handler = (typeof(handler))__get_mod_handler(type, 0); \
handler; \
handler = (typeof(handler))__get_mod_handler(type, ++(i)))
static int
__register_host_perm_fault_handler(int (*cb)(struct user_pt_regs *regs, u64 esr, u64 addr))
{
return mod_handler_register(HOST_FAULT_HANDLER, cb);
}
bool module_handle_host_perm_fault(struct user_pt_regs *regs, u64 esr, u64 addr)
{
int (*cb)(struct user_pt_regs *regs, u64 esr, u64 addr);
int i;
for_each_mod_handler(HOST_FAULT_HANDLER, cb, i) {
if (!cb(regs, esr, addr))
return true;
}
return false;
}
const struct pkvm_module_ops module_ops = {
.create_private_mapping = __pkvm_create_private_mapping,
.alloc_module_va = __pkvm_alloc_module_va,
@@ -143,7 +201,7 @@ const struct pkvm_module_ops module_ops = {
.flush_dcache_to_poc = __kvm_flush_dcache_to_poc,
.update_hcr_el2 = __update_hcr_el2,
.update_hfgwtr_el2 = __update_hfgwtr_el2,
.register_host_perm_fault_handler = hyp_register_host_perm_fault_handler,
.register_host_perm_fault_handler = __register_host_perm_fault_handler,
.host_stage2_mod_prot = module_change_host_page_prot,
.host_stage2_get_leaf = host_stage2_get_leaf,
.host_stage2_enable_lazy_pte = host_stage2_enable_lazy_pte,