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kvm: Put fake bios interrupt handlers into known memory area

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Instead of hacking boot protocol header better to place interrupt handlers into
BDA.

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
This commit is contained in:
Cyrill Gorcunov
2015-06-01 16:39:39 +01:00
committed by Will Deacon
parent bc75b0ae4d
commit 22489bb099
2 changed files with 19 additions and 15 deletions
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include/kvm/interrupt.h
+7
View File
@@ -3,6 +3,13 @@
#include <inttypes.h>
/*
* BIOS data area
*/
#define BDA_START 0xf0000
#define BDA_END 0xfffff
#define BDA_SIZE (BDA_END - BDA_START)
#define REAL_INTR_BASE 0x0000
#define REAL_INTR_VECTORS 256
kvm.c
+12 -15
View File
@@ -192,16 +192,17 @@ static int load_flat_binary(struct kvm *self, int fd)
#define BZ_KERNEL_START 0x100000UL
static const char *BZIMAGE_MAGIC = "HdrS";
static const char fakebios_vector[] = { 0xcf };
#define BZ_DEFAULT_SETUP_SECTS 4
static bool load_bzimage(struct kvm *self, int fd, const char *kernel_cmdline)
{
struct real_intr_desc intr;
struct boot_params boot, *t;
struct boot_params boot;
unsigned long setup_sects;
ssize_t setup_size;
void *p, *v;
void *p;
int nr;
/*
@@ -244,21 +245,17 @@ static bool load_bzimage(struct kvm *self, int fd, const char *kernel_cmdline)
self->boot_sp = BOOT_LOADER_SP;
/*
* Setup a *fake* real mode IVT, it has only one real
* hadler which does just iret
* Setup a *fake* real mode vector table, it has only
* one real hadler which does just iret
*
* we need a place for 1 byte so lets put
* it where the BIOS lives -- BDA area
*/
/*
* we need a place for 2 bytes so lets do
* a hack and use spare place in bootparams
*/
t = guest_real_to_host(self, BOOT_LOADER_SELECTOR, BOOT_LOADER_IP);
v = guest_flat_to_host(self, 0);
t->hdr._pad2[0] = 0xfb; /* sti */
t->hdr._pad2[1] = 0xcf; /* iret */
nr = (void *)&t->hdr._pad2[0] - v;
p = guest_flat_to_host(self, BDA_START);
memcpy(p, fakebios_vector, sizeof(fakebios_vector));
intr = (struct real_intr_desc) {
.segment = nr >> 4,
.offset = (nr - (nr & ~0xf)),
.segment = BDA_START >> 4,
.offset = 0,
};
p = guest_flat_to_host(self, 0);
interrupt_table__setup(&self->interrupt_table, &intr);