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Introduce guest mem offset, static link example launcher

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In order to avoid problematic special linking of the Launcher, we give
the Host an offset: this means we can use any memory region in the
Launcher as Guest memory rather than insisting on mmap() at 0.

The result is quite pleasing: a number of casts are replaced with
simple additions.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell
2007-10-22 11:03:26 +10:00
parent 6649bb7af6
commit 3c6b5bfa3c
8 changed files with 162 additions and 139 deletions
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22
drivers/lguest/core.c
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@@ -325,8 +325,8 @@ static int emulate_insn(struct lguest *lg)
* Dealing With Guest Memory.
*
* When the Guest gives us (what it thinks is) a physical address, we can use
* the normal copy_from_user() & copy_to_user() on that address: remember,
* Guest physical == Launcher virtual.
* the normal copy_from_user() & copy_to_user() on the corresponding place in
* the memory region allocated by the Launcher.
*
* But we can't trust the Guest: it might be trying to access the Launcher
* code. We have to check that the range is below the pfn_limit the Launcher
@@ -348,8 +348,8 @@ u32 lgread_u32(struct lguest *lg, unsigned long addr)
/* Don't let them access lguest binary. */
if (!lguest_address_ok(lg, addr, sizeof(val))
|| get_user(val, (u32 __user *)addr) != 0)
kill_guest(lg, "bad read address %#lx", addr);
|| get_user(val, (u32 *)(lg->mem_base + addr)) != 0)
kill_guest(lg, "bad read address %#lx: pfn_limit=%u membase=%p", addr, lg->pfn_limit, lg->mem_base);
return val;
}
@@ -357,7 +357,7 @@ u32 lgread_u32(struct lguest *lg, unsigned long addr)
void lgwrite_u32(struct lguest *lg, unsigned long addr, u32 val)
{
if (!lguest_address_ok(lg, addr, sizeof(val))
|| put_user(val, (u32 __user *)addr) != 0)
|| put_user(val, (u32 *)(lg->mem_base + addr)) != 0)
kill_guest(lg, "bad write address %#lx", addr);
}
@@ -367,7 +367,7 @@ void lgwrite_u32(struct lguest *lg, unsigned long addr, u32 val)
void lgread(struct lguest *lg, void *b, unsigned long addr, unsigned bytes)
{
if (!lguest_address_ok(lg, addr, bytes)
|| copy_from_user(b, (void __user *)addr, bytes) != 0) {
|| copy_from_user(b, lg->mem_base + addr, bytes) != 0) {
/* copy_from_user should do this, but as we rely on it... */
memset(b, 0, bytes);
kill_guest(lg, "bad read address %#lx len %u", addr, bytes);
@@ -379,7 +379,7 @@ void lgwrite(struct lguest *lg, unsigned long addr, const void *b,
unsigned bytes)
{
if (!lguest_address_ok(lg, addr, bytes)
|| copy_to_user((void __user *)addr, b, bytes) != 0)
|| copy_to_user(lg->mem_base + addr, b, bytes) != 0)
kill_guest(lg, "bad write address %#lx len %u", addr, bytes);
}
/* (end of memory access helper routines) :*/
@@ -616,11 +616,9 @@ int run_guest(struct lguest *lg, unsigned long __user *user)
*
* Note that if the Guest were really messed up, this
* could happen before it's done the INITIALIZE
* hypercall, so lg->lguest_data will be NULL, so
* &lg->lguest_data->cr2 will be address 8. Writing
* into that address won't hurt the Host at all,
* though. */
if (put_user(cr2, &lg->lguest_data->cr2))
* hypercall, so lg->lguest_data will be NULL */
if (lg->lguest_data
&& put_user(cr2, &lg->lguest_data->cr2))
kill_guest(lg, "Writing cr2");
break;
case 7: /* We've intercepted a Device Not Available fault. */