Changes to GEARS core to allow for selective syscall host interface

diff --git a/palacios/include/gears/syscall_hijack.h b/palacios/include/gears/syscall_hijack.h
index 4db6088..abf65a0 100644 (file)
--- a/palacios/include/gears/syscall_hijack.h
+++ b/palacios/include/gears/syscall_hijack.h
@@ -20,6 +20,14 @@
 #ifndef __SYSCALL_HIJACK_H__
 #define __SYSCALL_HIJACK_H__
 
+#ifdef V3_CONFIG_EXT_SELECTIVE_SYSCALL_EXIT
+int v3_syscall_on (void * ginfo, uint8_t syscall_nr);
+int v3_syscall_off (void * ginfo, uint8_t syscall_nr);
+int v3_syscall_stat (void * ginfo, uint8_t syscall_nr);
+
+#endif
+#ifdef __V3VEE__
+
 #define STAR_MSR                 0xc0000081 /* Legacy mode SYSCALL target */
 #define LSTAR_MSR                0xc0000082 /* Long mode SYSCALL target */
 #define CSTAR_MSR                0xc0000083 /* compat mode SYSCALL target */
@@ -46,6 +54,10 @@
 
 #define KERNEL_PHYS_LOAD_ADDR    0x1000000
 
+// hcall numbers for fast system call exiting utility
+#define SYSCALL_HANDLE_HCALL   0x5CA11
+#define SYSCALL_SETUP_HCALL    0x5CA12
+#define SYSCALL_CLEANUP_HCALL  0x5CA13
 
 struct v3_syscall_info {
     uint64_t target_addr;
@@ -66,3 +78,5 @@ int v3_hook_passthrough_syscall (struct guest_info * core, uint_t syscall_nr);
 int v3_syscall_handler (struct guest_info * core, uint8_t vector, void * priv_data);
 
 #endif
+
+#endif

diff --git a/palacios/src/gears/ext_syscall_hijack.c b/palacios/src/gears/ext_syscall_hijack.c
index 56e1d36..51b55b1 100644 (file)
--- a/palacios/src/gears/ext_syscall_hijack.c
+++ b/palacios/src/gears/ext_syscall_hijack.c
@@ -113,11 +113,6 @@ int v3_syscall_handler (struct guest_info * core, uint8_t vector, void * priv_da
         core->rip = syscall_info.target_addr;
 #endif
 
-#ifdef V3_CONFIG_EXT_SELECTIVE_SYSCALL_EXIT
-    PrintDebug("In v3_syscall_handler: syscall_nr - %d\n", syscall_nr);
-#endif
-
-
     if (hook == NULL) {
 #ifdef V3_CONFIG_EXT_SYSCALL_PASSTHROUGH
         if (v3_hook_passthrough_syscall(core, syscall_nr) == -1) {
@@ -199,19 +194,36 @@ static int v3_handle_lstar_read (struct guest_info * core, uint_t msr, struct v3
 
 
 static int syscall_setup (struct guest_info * core, unsigned int hcall_id, void * priv_data) {
-       addr_t syscall_stub, syscall_map, ssa;
+       addr_t syscall_stub, syscall_map_gva, syscall_map_hva, ssa_gva, ssa_hva;
 
        syscall_stub = (addr_t)core->vm_regs.rbx;
-       syscall_map = (addr_t)core->vm_regs.rcx;
-       ssa = (addr_t)core->vm_regs.rdx;
+       syscall_map_gva = (addr_t)core->vm_regs.rcx;
+       ssa_gva = (addr_t)core->vm_regs.rdx;
 
-       PrintDebug("made it to syscall setup hypercall\n");
-       PrintDebug("\t&syscall_stub (rbx): %p\n\t&syscall_map (rcx): %p\n", (void*)syscall_stub, (void*)syscall_map);
-       PrintDebug("\t&ssa (rdx): %p\n", (void*)ssa);
+       PrintDebug("syscall setup hypercall:\n");
+       PrintDebug("\t&syscall_stub (rbx): %p\n\t&syscall_map (rcx): %p\n", (void*)syscall_stub, (void*)syscall_map_gva);
+       PrintDebug("\t&ssa (rdx): %p\n", (void*)ssa_gva);
 
+       // the guest vitual address of the asm syscall handling routine
        syscall_info.syscall_stub = syscall_stub;
-       syscall_info.syscall_map = (uint8_t*)syscall_map;
-       syscall_info.ssa = ssa;
+
+       
+       // now get the hva of the system call map so we can manipulate it in the VMM
+       if (v3_gva_to_hva(core, get_addr_linear(core, syscall_map_gva, &(core->segments.ds)), &syscall_map_hva) == 1) {
+               PrintError("Problem translating gva to hva for syscall map\n");
+               return -1;
+       }
+       
+       if (v3_gva_to_hva(core, get_addr_linear(core, ssa_gva, &(core->segments.ds)), &ssa_hva) == 1) {
+               PrintError("Problem translating gva to hva for syscall map\n");
+               return -1;
+       }
+       
+       PrintDebug("\t&syscall_map (hva): %p\n", (void*) syscall_map_hva);
+       PrintDebug("\t&ssa (hva): %p\n", (void*) ssa_hva);
+
+       syscall_info.syscall_map = (uint8_t*)syscall_map_hva;
+       syscall_info.ssa = ssa_hva;
 
        /* return the original syscall entry point */
        core->vm_regs.rax = syscall_info.target_addr;
@@ -231,40 +243,53 @@ static int syscall_cleanup (struct guest_info * core, unsigned int hcall_id, voi
 
 
 static int sel_syscall_handle (struct guest_info * core, unsigned int hcall_id, void * priv_data) {
-       int ret;
-       addr_t hva;
        struct v3_gprs regs;
        
-       PrintDebug("caught a selectively exited syscall!\n");
-       ret = v3_gva_to_hva(core, get_addr_linear(core, syscall_info.ssa, &(core->segments.ds)), &hva);
-       if (ret == -1) {
-               PrintError("Problem translating state save area address in sel_syscall_handle\n");
-               return -1;
-       }
+       PrintDebug("caught a selectively exited syscall\n");
        
     /* setup registers for handler routines. They should be in the same state
      * as when the system call was originally invoked */
        memcpy((void*)&regs, (void*)&core->vm_regs, sizeof(struct v3_gprs));
-       memcpy((void*)&core->vm_regs, (void*)hva, sizeof(struct v3_gprs));
+       memcpy((void*)&core->vm_regs, (void*)syscall_info.ssa, sizeof(struct v3_gprs));
        
-       v3_print_guest_state(core);
-
-       // TODO: call syscall-independent handler
+       //v3_print_guest_state(core);
+       v3_syscall_handler(core, 0, NULL);
        
-       memcpy((void*)hva, (void*)&core->vm_regs, sizeof(struct v3_gprs));
+       memcpy((void*)syscall_info.ssa, (void*)&core->vm_regs, sizeof(struct v3_gprs));
        memcpy((void*)&core->vm_regs, (void*)&regs,sizeof(struct v3_gprs));
        return 0;
 }
 
 
+// TODO: make these three functions guest-dependent
+int v3_syscall_on (void * ginfo, uint8_t syscall_nr) {
+    PrintDebug("Enabling exiting for syscall #%d\n", syscall_nr);
+    syscall_info.syscall_map[syscall_nr] = 1;
+    return 0;
+}
+
+
+int v3_syscall_off (void * ginfo, uint8_t syscall_nr) {
+    PrintDebug("Disabling exiting for syscall #%d\n", syscall_nr);
+    syscall_info.syscall_map[syscall_nr] = 0;
+    return 0;
+}
+
+
+int v3_syscall_stat (void * ginfo, uint8_t syscall_nr) {
+    return syscall_info.syscall_map[syscall_nr];
+}
+
 #endif
 
 static int init_syscall_hijack (struct v3_vm_info * vm, v3_cfg_tree_t * cfg, void ** priv_data) {
+
 #ifdef V3_CONFIG_EXT_SELECTIVE_SYSCALL_EXIT
-       v3_register_hypercall(vm, 0x5CA11, sel_syscall_handle, NULL);
-       v3_register_hypercall(vm, 0x5CA12, syscall_setup, NULL);
-    v3_register_hypercall(vm, 0x5CA13, syscall_cleanup, NULL);
+       v3_register_hypercall(vm, SYSCALL_HANDLE_HCALL, sel_syscall_handle, NULL);
+       v3_register_hypercall(vm, SYSCALL_SETUP_HCALL, syscall_setup, NULL);
+       v3_register_hypercall(vm, SYSCALL_CLEANUP_HCALL, syscall_cleanup, NULL);
 #endif
+
     return 0;
 }