From 69d9918ddc7ffb7504b944ab01e0b432c9088ff6 Mon Sep 17 00:00:00 2001 From: Yonghua Huang Date: Tue, 15 May 2018 18:20:14 +0800 Subject: [PATCH] remove potential using default i/o handler - device driver should register valid i/o handlers in any cases, avoid referencing to default handler - remove i/o handler test code as they shall never be NULL. Signed-off-by: Yonghua Huang --- hypervisor/arch/x86/io.c | 34 +++++----------------------------- 1 file changed, 5 insertions(+), 29 deletions(-) diff --git a/hypervisor/arch/x86/io.c b/hypervisor/arch/x86/io.c index a0f484a92..e5bdc3d5e 100644 --- a/hypervisor/arch/x86/io.c +++ b/hypervisor/arch/x86/io.c @@ -116,9 +116,6 @@ int io_instr_vmexit_handler(struct vcpu *vcpu) } if (direction == 0) { - if (handler->desc.io_write == NULL) - continue; - handler->desc.io_write(handler, vm, port, sz, cur_context->guest_cpu_regs.regs.rax); @@ -127,7 +124,7 @@ int io_instr_vmexit_handler(struct vcpu *vcpu) status = 0; break; - } else if (handler->desc.io_read) { + } else { uint32_t data = handler->desc.io_read(handler, vm, port, sz); @@ -221,21 +218,6 @@ static void deny_guest_io_access(struct vm *vm, uint32_t address, uint32_t nbyte } } -static uint32_t -default_io_read(__unused struct vm_io_handler *hdlr, __unused struct vm *vm, - uint16_t address, size_t width) -{ - uint32_t v = io_read(address, width); - return v; -} - -static void default_io_write(__unused struct vm_io_handler *hdlr, - __unused struct vm *vm, uint16_t addr, - size_t width, uint32_t v) -{ - io_write(v, addr, width); -} - static struct vm_io_handler *create_io_handler(uint32_t port, uint32_t len, io_read_fn_t io_read_fn_ptr, io_write_fn_t io_write_fn_ptr) @@ -280,23 +262,17 @@ void register_io_emulation_handler(struct vm *vm, struct vm_io_range *range, io_write_fn_t io_write_fn_ptr) { struct vm_io_handler *handler = NULL; - io_read_fn_t io_read_fn = &default_io_read; - io_write_fn_t io_write_fn = &default_io_write; - if (range->flags == IO_ATTR_RW && io_read_fn_ptr && io_write_fn_ptr) { - io_read_fn = io_read_fn_ptr; - io_write_fn = io_write_fn_ptr; - } else if (range->flags == IO_ATTR_R) { - if (io_read_fn_ptr) - io_read_fn = io_read_fn_ptr; - io_write_fn = NULL; + if (io_read_fn_ptr == NULL || io_write_fn_ptr == NULL) { + pr_err("Invalid IO handler."); + return; } if (is_vm0(vm)) deny_guest_io_access(vm, range->base, range->len); handler = create_io_handler(range->base, - range->len, io_read_fn, io_write_fn); + range->len, io_read_fn_ptr, io_write_fn_ptr); register_io_handler(vm, handler); }