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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen stable-4.16] x86/HVM: remove unused MMIO handling code
commit 58698a18e4714ca7d02858fce821b11f3f194d18
Author: Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Nov 12 14:13:20 2024 +0100
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Nov 12 14:13:20 2024 +0100
x86/HVM: remove unused MMIO handling code
All read accesses are rejected by the ->accept handler, while writes
bypass the bulk of the function body. Drop the dead code, leaving an
assertion in the read handler.
A number of other static items (and a macro) are then unreferenced and
hence also need (want) dropping. The same applies to the "latch" field
of the state structure.
This is part of XSA-463 / CVE-2024-45818
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
(cherry picked from commit 89108547af1f230b72893b48351f9c1106189649)
---
xen/arch/x86/hvm/stdvga.c | 317 +------------------------------------------
xen/include/asm-x86/hvm/io.h | 1 -
2 files changed, 4 insertions(+), 314 deletions(-)
diff --git a/xen/arch/x86/hvm/stdvga.c b/xen/arch/x86/hvm/stdvga.c
index a5f1cff017..138ced229d 100644
--- a/xen/arch/x86/hvm/stdvga.c
+++ b/xen/arch/x86/hvm/stdvga.c
@@ -38,26 +38,6 @@
#define VGA_MEM_BASE 0xa0000
#define VGA_MEM_SIZE 0x20000
-#define PAT(x) (x)
-static const uint32_t mask16[16] = {
- PAT(0x00000000),
- PAT(0x000000ff),
- PAT(0x0000ff00),
- PAT(0x0000ffff),
- PAT(0x00ff0000),
- PAT(0x00ff00ff),
- PAT(0x00ffff00),
- PAT(0x00ffffff),
- PAT(0xff000000),
- PAT(0xff0000ff),
- PAT(0xff00ff00),
- PAT(0xff00ffff),
- PAT(0xffff0000),
- PAT(0xffff00ff),
- PAT(0xffffff00),
- PAT(0xffffffff),
-};
-
/* force some bits to zero */
static const uint8_t sr_mask[8] = {
(uint8_t)~0xfc,
@@ -82,25 +62,6 @@ static const uint8_t gr_mask[9] = {
(uint8_t)~0x00, /* 0x08 */
};
-static uint8_t *vram_getb(struct hvm_hw_stdvga *s, unsigned int a)
-{
- struct page_info *pg = s->vram_page[(a >> 12) & 0x3f];
- uint8_t *p = __map_domain_page(pg);
- return &p[a & 0xfff];
-}
-
-static uint32_t *vram_getl(struct hvm_hw_stdvga *s, unsigned int a)
-{
- struct page_info *pg = s->vram_page[(a >> 10) & 0x3f];
- uint32_t *p = __map_domain_page(pg);
- return &p[a & 0x3ff];
-}
-
-static void vram_put(struct hvm_hw_stdvga *s, void *p)
-{
- unmap_domain_page(p);
-}
-
static int stdvga_outb(uint64_t addr, uint8_t val)
{
struct hvm_hw_stdvga *s = ¤t->domain->arch.hvm.stdvga;
@@ -169,243 +130,12 @@ static int stdvga_intercept_pio(
return X86EMUL_UNHANDLEABLE; /* propagate to external ioemu */
}
-static unsigned int stdvga_mem_offset(
- struct hvm_hw_stdvga *s, unsigned int mmio_addr)
-{
- unsigned int memory_map_mode = (s->gr[6] >> 2) & 3;
- unsigned int offset = mmio_addr & 0x1ffff;
-
- switch ( memory_map_mode )
- {
- case 0:
- break;
- case 1:
- if ( offset >= 0x10000 )
- goto fail;
- offset += 0; /* assume bank_offset == 0; */
- break;
- case 2:
- offset -= 0x10000;
- if ( offset >= 0x8000 )
- goto fail;
- break;
- default:
- case 3:
- offset -= 0x18000;
- if ( offset >= 0x8000 )
- goto fail;
- break;
- }
-
- return offset;
-
- fail:
- return ~0u;
-}
-
-#define GET_PLANE(data, p) (((data) >> ((p) * 8)) & 0xff)
-
-static uint8_t stdvga_mem_readb(uint64_t addr)
-{
- struct hvm_hw_stdvga *s = ¤t->domain->arch.hvm.stdvga;
- int plane;
- uint32_t ret, *vram_l;
- uint8_t *vram_b;
-
- addr = stdvga_mem_offset(s, addr);
- if ( addr == ~0u )
- return 0xff;
-
- if ( s->sr[4] & 0x08 )
- {
- /* chain 4 mode : simplest access */
- vram_b = vram_getb(s, addr);
- ret = *vram_b;
- vram_put(s, vram_b);
- }
- else if ( s->gr[5] & 0x10 )
- {
- /* odd/even mode (aka text mode mapping) */
- plane = (s->gr[4] & 2) | (addr & 1);
- vram_b = vram_getb(s, ((addr & ~1) << 1) | plane);
- ret = *vram_b;
- vram_put(s, vram_b);
- }
- else
- {
- /* standard VGA latched access */
- vram_l = vram_getl(s, addr);
- s->latch = *vram_l;
- vram_put(s, vram_l);
-
- if ( !(s->gr[5] & 0x08) )
- {
- /* read mode 0 */
- plane = s->gr[4];
- ret = GET_PLANE(s->latch, plane);
- }
- else
- {
- /* read mode 1 */
- ret = (s->latch ^ mask16[s->gr[2]]) & mask16[s->gr[7]];
- ret |= ret >> 16;
- ret |= ret >> 8;
- ret = (~ret) & 0xff;
- }
- }
-
- return ret;
-}
-
static int stdvga_mem_read(const struct hvm_io_handler *handler,
uint64_t addr, uint32_t size, uint64_t *p_data)
{
- uint64_t data = ~0ul;
-
- switch ( size )
- {
- case 1:
- data = stdvga_mem_readb(addr);
- break;
-
- case 2:
- data = stdvga_mem_readb(addr);
- data |= stdvga_mem_readb(addr + 1) << 8;
- break;
-
- case 4:
- data = stdvga_mem_readb(addr);
- data |= stdvga_mem_readb(addr + 1) << 8;
- data |= stdvga_mem_readb(addr + 2) << 16;
- data |= (uint32_t)stdvga_mem_readb(addr + 3) << 24;
- break;
-
- case 8:
- data = (uint64_t)(stdvga_mem_readb(addr));
- data |= (uint64_t)(stdvga_mem_readb(addr + 1)) << 8;
- data |= (uint64_t)(stdvga_mem_readb(addr + 2)) << 16;
- data |= (uint64_t)(stdvga_mem_readb(addr + 3)) << 24;
- data |= (uint64_t)(stdvga_mem_readb(addr + 4)) << 32;
- data |= (uint64_t)(stdvga_mem_readb(addr + 5)) << 40;
- data |= (uint64_t)(stdvga_mem_readb(addr + 6)) << 48;
- data |= (uint64_t)(stdvga_mem_readb(addr + 7)) << 56;
- break;
-
- default:
- gdprintk(XENLOG_WARNING, "invalid io size: %u\n", size);
- break;
- }
-
- *p_data = data;
- return X86EMUL_OKAY;
-}
-
-static void stdvga_mem_writeb(uint64_t addr, uint32_t val)
-{
- struct hvm_hw_stdvga *s = ¤t->domain->arch.hvm.stdvga;
- int plane, write_mode, b, func_select, mask;
- uint32_t write_mask, bit_mask, set_mask, *vram_l;
- uint8_t *vram_b;
-
- addr = stdvga_mem_offset(s, addr);
- if ( addr == ~0u )
- return;
-
- if ( s->sr[4] & 0x08 )
- {
- /* chain 4 mode : simplest access */
- plane = addr & 3;
- mask = (1 << plane);
- if ( s->sr[2] & mask )
- {
- vram_b = vram_getb(s, addr);
- *vram_b = val;
- vram_put(s, vram_b);
- }
- }
- else if ( s->gr[5] & 0x10 )
- {
- /* odd/even mode (aka text mode mapping) */
- plane = (s->gr[4] & 2) | (addr & 1);
- mask = (1 << plane);
- if ( s->sr[2] & mask )
- {
- addr = ((addr & ~1) << 1) | plane;
- vram_b = vram_getb(s, addr);
- *vram_b = val;
- vram_put(s, vram_b);
- }
- }
- else
- {
- write_mode = s->gr[5] & 3;
- switch ( write_mode )
- {
- default:
- case 0:
- /* rotate */
- b = s->gr[3] & 7;
- val = ((val >> b) | (val << (8 - b))) & 0xff;
- val |= val << 8;
- val |= val << 16;
-
- /* apply set/reset mask */
- set_mask = mask16[s->gr[1]];
- val = (val & ~set_mask) | (mask16[s->gr[0]] & set_mask);
- bit_mask = s->gr[8];
- break;
- case 1:
- val = s->latch;
- goto do_write;
- case 2:
- val = mask16[val & 0x0f];
- bit_mask = s->gr[8];
- break;
- case 3:
- /* rotate */
- b = s->gr[3] & 7;
- val = (val >> b) | (val << (8 - b));
-
- bit_mask = s->gr[8] & val;
- val = mask16[s->gr[0]];
- break;
- }
-
- /* apply logical operation */
- func_select = s->gr[3] >> 3;
- switch ( func_select )
- {
- case 0:
- default:
- /* nothing to do */
- break;
- case 1:
- /* and */
- val &= s->latch;
- break;
- case 2:
- /* or */
- val |= s->latch;
- break;
- case 3:
- /* xor */
- val ^= s->latch;
- break;
- }
-
- /* apply bit mask */
- bit_mask |= bit_mask << 8;
- bit_mask |= bit_mask << 16;
- val = (val & bit_mask) | (s->latch & ~bit_mask);
-
- do_write:
- /* mask data according to sr[2] */
- mask = s->sr[2];
- write_mask = mask16[mask];
- vram_l = vram_getl(s, addr);
- *vram_l = (*vram_l & ~write_mask) | (val & write_mask);
- vram_put(s, vram_l);
- }
+ ASSERT_UNREACHABLE();
+ *p_data = ~0;
+ return X86EMUL_UNHANDLEABLE;
}
static int stdvga_mem_write(const struct hvm_io_handler *handler,
@@ -420,47 +150,8 @@ static int stdvga_mem_write(const struct hvm_io_handler
*handler,
.dir = IOREQ_WRITE,
.data = data,
};
- struct ioreq_server *srv;
-
- goto done;
-
- /* Intercept mmio write */
- switch ( size )
- {
- case 1:
- stdvga_mem_writeb(addr, (data >> 0) & 0xff);
- break;
-
- case 2:
- stdvga_mem_writeb(addr+0, (data >> 0) & 0xff);
- stdvga_mem_writeb(addr+1, (data >> 8) & 0xff);
- break;
-
- case 4:
- stdvga_mem_writeb(addr+0, (data >> 0) & 0xff);
- stdvga_mem_writeb(addr+1, (data >> 8) & 0xff);
- stdvga_mem_writeb(addr+2, (data >> 16) & 0xff);
- stdvga_mem_writeb(addr+3, (data >> 24) & 0xff);
- break;
-
- case 8:
- stdvga_mem_writeb(addr+0, (data >> 0) & 0xff);
- stdvga_mem_writeb(addr+1, (data >> 8) & 0xff);
- stdvga_mem_writeb(addr+2, (data >> 16) & 0xff);
- stdvga_mem_writeb(addr+3, (data >> 24) & 0xff);
- stdvga_mem_writeb(addr+4, (data >> 32) & 0xff);
- stdvga_mem_writeb(addr+5, (data >> 40) & 0xff);
- stdvga_mem_writeb(addr+6, (data >> 48) & 0xff);
- stdvga_mem_writeb(addr+7, (data >> 56) & 0xff);
- break;
-
- default:
- gdprintk(XENLOG_WARNING, "invalid io size: %u\n", size);
- break;
- }
+ struct ioreq_server *srv = ioreq_server_select(current->domain, &p);
- done:
- srv = ioreq_server_select(current->domain, &p);
if ( !srv )
return X86EMUL_UNHANDLEABLE;
diff --git a/xen/include/asm-x86/hvm/io.h b/xen/include/asm-x86/hvm/io.h
index d964f8efdf..7bd1fa113e 100644
--- a/xen/include/asm-x86/hvm/io.h
+++ b/xen/include/asm-x86/hvm/io.h
@@ -126,7 +126,6 @@ struct hvm_hw_stdvga {
uint8_t sr[8];
uint8_t gr_index;
uint8_t gr[9];
- uint32_t latch;
struct page_info *vram_page[64]; /* shadow of 0xa0000-0xaffff */
spinlock_t lock;
};
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.16
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