Assure that unhandled IO reads get back zeros

[palacios.git] / palacios / src / palacios / svm_io.c

diff --git a/palacios/src/palacios/svm_io.c b/palacios/src/palacios/svm_io.c
index aaa6101..4ad954d 100644 (file)
--- a/palacios/src/palacios/svm_io.c
+++ b/palacios/src/palacios/svm_io.c
@@ -24,7 +24,7 @@
 #include <palacios/vmm_decoder.h>
 #include <palacios/vm_guest_mem.h>
 
-#ifndef CONFIG_DEBUG_IO
+#ifndef V3_CONFIG_DEBUG_IO
 #undef PrintDebug
 #define PrintDebug(fmt, args...)
 #endif
@@ -49,7 +49,7 @@ int v3_init_svm_io_map(struct v3_vm_info * vm) {
     vm->io_map.update_map = update_map;
 
     vm->io_map.arch_data = V3_VAddr(V3_AllocPages(3));
-    memset(vm->io_map.arch_data, 0, PAGE_SIZE_4KB * 3);
+    memset(vm->io_map.arch_data, 0xff, PAGE_SIZE_4KB * 3);
 
 
     v3_refresh_io_map(vm);
@@ -57,6 +57,11 @@ int v3_init_svm_io_map(struct v3_vm_info * vm) {
     return 0;
 }
 
+int v3_deinit_svm_io_map(struct v3_vm_info * vm) {
+    V3_FreePages(V3_PAddr(vm->io_map.arch_data), 3);
+    return 0;
+}
+
 
 
 // This should package up an IO request and call vmm_handle_io
@@ -64,13 +69,6 @@ int v3_handle_svm_io_in(struct guest_info * core, struct svm_io_info * io_info)
     struct v3_io_hook * hook = v3_get_io_hook(core->vm_info, io_info->port);
     int read_size = 0;
 
-    if (hook == NULL) {
-       PrintError("Hook Not present for in on port 0x%x\n", io_info->port);
-       // error, we should not have exited on this port
-       return -1;
-    }
-
-
     if (io_info->sz8) { 
        read_size = 1;
     } else if (io_info->sz16) {
@@ -81,11 +79,19 @@ int v3_handle_svm_io_in(struct guest_info * core, struct svm_io_info * io_info)
 
     PrintDebug("IN of %d bytes on port %d (0x%x)\n", read_size, io_info->port, io_info->port);
 
-    if (hook->read(core, io_info->port, &(core->vm_regs.rax), read_size, hook->priv_data) != read_size) {
-       // not sure how we handle errors.....
-       PrintError("Read Failure for in on port 0x%x\n", io_info->port);
-       return -1;
+    if (hook == NULL) {
+       PrintDebug("IN operation on unhooked IO port 0x%x - returning zero\n", io_info->port);
+       core->vm_regs.rax >>= 8*read_size;
+       core->vm_regs.rax <<= 8*read_size;
+
+    } else {
+       if (hook->read(core, io_info->port, &(core->vm_regs.rax), read_size, hook->priv_data) != read_size) {
+           // not sure how we handle errors.....
+           PrintError("Read Failure for in on port 0x%x\n", io_info->port);
+           return -1;
+       }
     }
+    
 
     return 0;
 }
@@ -116,15 +122,7 @@ int v3_handle_svm_io_ins(struct guest_info * core, struct svm_io_info * io_info)
     if (flags->df) {
        direction = -1;
     }
-
-
-    if (hook == NULL) {
-       PrintError("Hook Not present for ins on port 0x%x\n", io_info->port);
-       // error, we should not have exited on this port
-       return -1;
-    }
-
-
+    
 
     if (v3_gva_to_hva(core, get_addr_linear(core, core->rip, &(core->segments.cs)), &inst_ptr) == -1) {
        PrintError("Can't access instruction\n");
@@ -193,7 +191,6 @@ int v3_handle_svm_io_ins(struct guest_info * core, struct svm_io_info * io_info)
        //rep_num = info->vm_regs.rcx;
     }
 
-
     PrintDebug("INS size=%d for %d steps\n", read_size, rep_num);
 
     while (rep_num > 0) {
@@ -208,12 +205,18 @@ int v3_handle_svm_io_ins(struct guest_info * core, struct svm_io_info * io_info)
            return -1;
        }
 
-       if (hook->read(core, io_info->port, (char *)host_addr, read_size, hook->priv_data) != read_size) {
-           // not sure how we handle errors.....
-           PrintError("Read Failure for ins on port 0x%x\n", io_info->port);
-           return -1;
+       if (hook == NULL) {
+           PrintDebug("INS operation on unhooked IO port 0x%x - returning zeros\n", io_info->port);
+           memset((char*)host_addr,0,read_size);
+           
+       } else {
+           if (hook->read(core, io_info->port, (char *)host_addr, read_size, hook->priv_data) != read_size) {
+               // not sure how we handle errors.....
+               PrintError("Read Failure for ins on port 0x%x\n", io_info->port);
+               return -1;
+           }
        }
-
+    
        core->vm_regs.rdi += (read_size * direction);
 
        if (io_info->rep) {
@@ -230,13 +233,6 @@ int v3_handle_svm_io_out(struct guest_info * core, struct svm_io_info * io_info)
     struct v3_io_hook * hook = v3_get_io_hook(core->vm_info, io_info->port);
     int write_size = 0;
 
-    if (hook == NULL) {
-       PrintError("Hook Not present for out on port 0x%x\n", io_info->port);
-       // error, we should not have exited on this port
-       return -1;
-    }
-
-
     if (io_info->sz8) { 
        write_size = 1;
     } else if (io_info->sz16) {
@@ -247,11 +243,16 @@ int v3_handle_svm_io_out(struct guest_info * core, struct svm_io_info * io_info)
 
     PrintDebug("OUT of %d bytes on  port %d (0x%x)\n", write_size, io_info->port, io_info->port);
 
-    if (hook->write(core, io_info->port, &(core->vm_regs.rax), write_size, hook->priv_data) != write_size) {
-       // not sure how we handle errors.....
-       PrintError("Write Failure for out on port 0x%x\n", io_info->port);
-       return -1;
+    if (hook == NULL) {
+       PrintDebug("OUT operation on unhooked IO port 0x%x - ignored\n", io_info->port);
+    } else {
+       if (hook->write(core, io_info->port, &(core->vm_regs.rax), write_size, hook->priv_data) != write_size) {
+           // not sure how we handle errors.....
+           PrintError("Write Failure for out on port 0x%x\n", io_info->port);
+           return -1;
+       }
     }
+    
 
     return 0;
 }
@@ -269,7 +270,7 @@ int v3_handle_svm_io_outs(struct guest_info * core, struct svm_io_info * io_info
     uint_t rep_num = 1;
     ullong_t mask = 0;
     addr_t inst_ptr;
-    struct v3_segment * theseg = &(core->segments.es); // default is ES
+    struct v3_segment * theseg = &(core->segments.ds); // default is DS
 
     // This is kind of hacky...
     // direction can equal either 1 or -1
@@ -281,13 +282,6 @@ int v3_handle_svm_io_outs(struct guest_info * core, struct svm_io_info * io_info
        direction = -1;
     }
 
-
-    if (hook == NULL) {
-       PrintError("Hook Not present for outs on port 0x%x\n", io_info->port);
-       // error, we should not have exited on this port
-       return -1;
-    }
-
     PrintDebug("OUTS on  port %d (0x%x)\n", io_info->port, io_info->port);
 
     if (io_info->sz8) { 
@@ -359,19 +353,25 @@ int v3_handle_svm_io_outs(struct guest_info * core, struct svm_io_info * io_info
     PrintDebug("OUTS size=%d for %d steps\n", write_size, rep_num);
 
     while (rep_num > 0) {
-       addr_t host_addr;
+       addr_t host_addr = 0;
 
        dst_addr = get_addr_linear(core, (core->vm_regs.rsi & mask), theseg);
     
        if (v3_gva_to_hva(core, dst_addr, &host_addr) == -1) {
-           // either page fault or gpf...
+           PrintError("Could not translate outs dest addr, either page fault or gpf...\n");
+           return -1;
        }
 
-       if (hook->write(core, io_info->port, (char*)host_addr, write_size, hook->priv_data) != write_size) {
-           // not sure how we handle errors.....
-           PrintError("Write Failure for outs on port 0x%x\n", io_info->port);
-           return -1;
+       if (hook == NULL) {
+           PrintDebug("OUTS operation on unhooked IO port 0x%x - ignored\n", io_info->port);
+       } else {
+           if (hook->write(core, io_info->port, (char*)host_addr, write_size, hook->priv_data) != write_size) {
+               // not sure how we handle errors.....
+               PrintError("Write Failure for outs on port 0x%x\n", io_info->port);
+               return -1;
+           }
        }
+       
 
        core->vm_regs.rsi += write_size * direction;