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lguest: make hypercalls use the vcpu struct
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this patch changes do_hcall() and do_async_hcall() interfaces (and obviously their
callers) to get a vcpu struct. Again, a vcpu services the hypercall, not the whole
guest

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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Glauber de Oliveira Costa authored and Rusty Russell committed Jan 30, 2008
1 parent 7ea07a1 commit 73044f0
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Showing 4 changed files with 44 additions and 36 deletions.
6 changes: 3 additions & 3 deletions drivers/lguest/core.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -181,8 +181,8 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
/* We stop running once the Guest is dead. */
while (!lg->dead) {
/* First we run any hypercalls the Guest wants done. */
if (lg->hcall)
do_hypercalls(lg);
if (cpu->hcall)
do_hypercalls(cpu);

/* It's possible the Guest did a NOTIFY hypercall to the
* Launcher, in which case we return from the read() now. */
Expand Down Expand Up @@ -234,7 +234,7 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
local_irq_enable();

/* Now we deal with whatever happened to the Guest. */
lguest_arch_handle_trap(lg);
lguest_arch_handle_trap(cpu);
}

if (lg->dead == ERR_PTR(-ERESTART))
Expand Down
42 changes: 23 additions & 19 deletions drivers/lguest/hypercalls.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -29,8 +29,10 @@

/*H:120 This is the core hypercall routine: where the Guest gets what it wants.
* Or gets killed. Or, in the case of LHCALL_CRASH, both. */
static void do_hcall(struct lguest *lg, struct hcall_args *args)
static void do_hcall(struct lg_cpu *cpu, struct hcall_args *args)
{
struct lguest *lg = cpu->lg;

switch (args->arg0) {
case LHCALL_FLUSH_ASYNC:
/* This call does nothing, except by breaking out of the Guest
Expand Down Expand Up @@ -93,7 +95,7 @@ static void do_hcall(struct lguest *lg, struct hcall_args *args)
break;
default:
/* It should be an architecture-specific hypercall. */
if (lguest_arch_do_hcall(lg, args))
if (lguest_arch_do_hcall(cpu, args))
kill_guest(lg, "Bad hypercall %li\n", args->arg0);
}
}
Expand All @@ -106,10 +108,11 @@ static void do_hcall(struct lguest *lg, struct hcall_args *args)
* Guest put them in the ring, but we also promise the Guest that they will
* happen before any normal hypercall (which is why we check this before
* checking for a normal hcall). */
static void do_async_hcalls(struct lguest *lg)
static void do_async_hcalls(struct lg_cpu *cpu)
{
unsigned int i;
u8 st[LHCALL_RING_SIZE];
struct lguest *lg = cpu->lg;

/* For simplicity, we copy the entire call status array in at once. */
if (copy_from_user(&st, &lg->lguest_data->hcall_status, sizeof(st)))
Expand All @@ -121,16 +124,16 @@ static void do_async_hcalls(struct lguest *lg)
/* We remember where we were up to from last time. This makes
* sure that the hypercalls are done in the order the Guest
* places them in the ring. */
unsigned int n = lg->next_hcall;
unsigned int n = cpu->next_hcall;

/* 0xFF means there's no call here (yet). */
if (st[n] == 0xFF)
break;

/* OK, we have hypercall. Increment the "next_hcall" cursor,
* and wrap back to 0 if we reach the end. */
if (++lg->next_hcall == LHCALL_RING_SIZE)
lg->next_hcall = 0;
if (++cpu->next_hcall == LHCALL_RING_SIZE)
cpu->next_hcall = 0;

/* Copy the hypercall arguments into a local copy of
* the hcall_args struct. */
Expand All @@ -141,7 +144,7 @@ static void do_async_hcalls(struct lguest *lg)
}

/* Do the hypercall, same as a normal one. */
do_hcall(lg, &args);
do_hcall(cpu, &args);

/* Mark the hypercall done. */
if (put_user(0xFF, &lg->lguest_data->hcall_status[n])) {
Expand All @@ -158,16 +161,17 @@ static void do_async_hcalls(struct lguest *lg)

/* Last of all, we look at what happens first of all. The very first time the
* Guest makes a hypercall, we end up here to set things up: */
static void initialize(struct lguest *lg)
static void initialize(struct lg_cpu *cpu)
{
struct lguest *lg = cpu->lg;
/* You can't do anything until you're initialized. The Guest knows the
* rules, so we're unforgiving here. */
if (lg->hcall->arg0 != LHCALL_LGUEST_INIT) {
kill_guest(lg, "hypercall %li before INIT", lg->hcall->arg0);
if (cpu->hcall->arg0 != LHCALL_LGUEST_INIT) {
kill_guest(lg, "hypercall %li before INIT", cpu->hcall->arg0);
return;
}

if (lguest_arch_init_hypercalls(lg))
if (lguest_arch_init_hypercalls(cpu))
kill_guest(lg, "bad guest page %p", lg->lguest_data);

/* The Guest tells us where we're not to deliver interrupts by putting
Expand Down Expand Up @@ -196,27 +200,27 @@ static void initialize(struct lguest *lg)
* Remember from the Guest, hypercalls come in two flavors: normal and
* asynchronous. This file handles both of types.
*/
void do_hypercalls(struct lguest *lg)
void do_hypercalls(struct lg_cpu *cpu)
{
/* Not initialized yet? This hypercall must do it. */
if (unlikely(!lg->lguest_data)) {
if (unlikely(!cpu->lg->lguest_data)) {
/* Set up the "struct lguest_data" */
initialize(lg);
initialize(cpu);
/* Hcall is done. */
lg->hcall = NULL;
cpu->hcall = NULL;
return;
}

/* The Guest has initialized.
*
* Look in the hypercall ring for the async hypercalls: */
do_async_hcalls(lg);
do_async_hcalls(cpu);

/* If we stopped reading the hypercall ring because the Guest did a
* NOTIFY to the Launcher, we want to return now. Otherwise we do
* the hypercall. */
if (!lg->pending_notify) {
do_hcall(lg, lg->hcall);
if (!cpu->lg->pending_notify) {
do_hcall(cpu, cpu->hcall);
/* Tricky point: we reset the hcall pointer to mark the
* hypercall as "done". We use the hcall pointer rather than
* the trap number to indicate a hypercall is pending.
Expand All @@ -227,7 +231,7 @@ void do_hypercalls(struct lguest *lg)
* Launcher, the run_guest() loop will exit without running the
* Guest. When it comes back it would try to re-run the
* hypercall. */
lg->hcall = NULL;
cpu->hcall = NULL;
}
}

Expand Down
16 changes: 8 additions & 8 deletions drivers/lguest/lg.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -43,6 +43,10 @@ struct lguest;
struct lg_cpu {
unsigned int id;
struct lguest *lg;

/* If a hypercall was asked for, this points to the arguments. */
struct hcall_args *hcall;
u32 next_hcall;
};

/* The private info the thread maintains about the guest. */
Expand All @@ -65,13 +69,9 @@ struct lguest
u32 cr2;
int halted;
int ts;
u32 next_hcall;
u32 esp1;
u8 ss1;

/* If a hypercall was asked for, this points to the arguments. */
struct hcall_args *hcall;

/* Do we need to stop what we're doing and return to userspace? */
int break_out;
wait_queue_head_t break_wq;
Expand Down Expand Up @@ -178,9 +178,9 @@ void page_table_guest_data_init(struct lguest *lg);
void lguest_arch_host_init(void);
void lguest_arch_host_fini(void);
void lguest_arch_run_guest(struct lg_cpu *cpu);
void lguest_arch_handle_trap(struct lguest *lg);
int lguest_arch_init_hypercalls(struct lguest *lg);
int lguest_arch_do_hcall(struct lguest *lg, struct hcall_args *args);
void lguest_arch_handle_trap(struct lg_cpu *cpu);
int lguest_arch_init_hypercalls(struct lg_cpu *cpu);
int lguest_arch_do_hcall(struct lg_cpu *cpu, struct hcall_args *args);
void lguest_arch_setup_regs(struct lguest *lg, unsigned long start);

/* <arch>/switcher.S: */
Expand All @@ -191,7 +191,7 @@ int lguest_device_init(void);
void lguest_device_remove(void);

/* hypercalls.c: */
void do_hypercalls(struct lguest *lg);
void do_hypercalls(struct lg_cpu *cpu);
void write_timestamp(struct lguest *lg);

/*L:035
Expand Down
16 changes: 10 additions & 6 deletions drivers/lguest/x86/core.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -283,8 +283,9 @@ static int emulate_insn(struct lguest *lg)
}

/*H:050 Once we've re-enabled interrupts, we look at why the Guest exited. */
void lguest_arch_handle_trap(struct lguest *lg)
void lguest_arch_handle_trap(struct lg_cpu *cpu)
{
struct lguest *lg = cpu->lg;
switch (lg->regs->trapnum) {
case 13: /* We've intercepted a General Protection Fault. */
/* Check if this was one of those annoying IN or OUT
Expand Down Expand Up @@ -336,7 +337,7 @@ void lguest_arch_handle_trap(struct lguest *lg)
case LGUEST_TRAP_ENTRY:
/* Our 'struct hcall_args' maps directly over our regs: we set
* up the pointer now to indicate a hypercall is pending. */
lg->hcall = (struct hcall_args *)lg->regs;
cpu->hcall = (struct hcall_args *)lg->regs;
return;
}

Expand Down Expand Up @@ -491,8 +492,10 @@ void __exit lguest_arch_host_fini(void)


/*H:122 The i386-specific hypercalls simply farm out to the right functions. */
int lguest_arch_do_hcall(struct lguest *lg, struct hcall_args *args)
int lguest_arch_do_hcall(struct lg_cpu *cpu, struct hcall_args *args)
{
struct lguest *lg = cpu->lg;

switch (args->arg0) {
case LHCALL_LOAD_GDT:
load_guest_gdt(lg, args->arg1, args->arg2);
Expand All @@ -511,21 +514,22 @@ int lguest_arch_do_hcall(struct lguest *lg, struct hcall_args *args)
}

/*H:126 i386-specific hypercall initialization: */
int lguest_arch_init_hypercalls(struct lguest *lg)
int lguest_arch_init_hypercalls(struct lg_cpu *cpu)
{
u32 tsc_speed;
struct lguest *lg = cpu->lg;

/* The pointer to the Guest's "struct lguest_data" is the only
* argument. We check that address now. */
if (!lguest_address_ok(lg, lg->hcall->arg1, sizeof(*lg->lguest_data)))
if (!lguest_address_ok(lg, cpu->hcall->arg1, sizeof(*lg->lguest_data)))
return -EFAULT;

/* Having checked it, we simply set lg->lguest_data to point straight
* into the Launcher's memory at the right place and then use
* copy_to_user/from_user from now on, instead of lgread/write. I put
* this in to show that I'm not immune to writing stupid
* optimizations. */
lg->lguest_data = lg->mem_base + lg->hcall->arg1;
lg->lguest_data = lg->mem_base + cpu->hcall->arg1;

/* We insist that the Time Stamp Counter exist and doesn't change with
* cpu frequency. Some devious chip manufacturers decided that TSC
Expand Down

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