[xen staging-4.17] x86/HVM: drop stdvga's "{g,s}r_index" struct members

[patchbot@xxxxxxx]

commit f65f18ec68ff2acb4b3cef6b0b1917615f63a4bd
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Nov 12 14:08:44 2024 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Nov 12 14:08:44 2024 +0100

    x86/HVM: drop stdvga's "{g,s}r_index" struct members
    
    No consumers are left, hence the producer and the fields themselves can
    also go away. stdvga_outb() is then useless, rendering stdvga_out()
    useless as well. Hence the entire I/O port intercept can go away.
    
    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 86c03372e107f5c18266a62281663861b1144929)
---
 xen/arch/x86/hvm/stdvga.c         | 61 ---------------------------------------
 xen/arch/x86/include/asm/hvm/io.h |  2 --
 2 files changed, 63 deletions(-)

diff --git a/xen/arch/x86/hvm/stdvga.c b/xen/arch/x86/hvm/stdvga.c
index 818dba67d7..029328b4b1 100644
--- a/xen/arch/x86/hvm/stdvga.c
+++ b/xen/arch/x86/hvm/stdvga.c
@@ -38,62 +38,6 @@
 #define VGA_MEM_BASE 0xa0000
 #define VGA_MEM_SIZE 0x20000
 
-static int stdvga_outb(uint64_t addr, uint8_t val)
-{
-    struct hvm_hw_stdvga *s = &current->domain->arch.hvm.stdvga;
-    int rc = 1;
-
-    switch ( addr )
-    {
-    case 0x3c4:                 /* sequencer address register */
-        s->sr_index = val;
-        break;
-
-    case 0x3ce:                 /* graphics address register */
-        s->gr_index = val;
-        break;
-
-    default:
-        rc = 0;
-        break;
-    }
-
-    return rc;
-}
-
-static void stdvga_out(uint32_t port, uint32_t bytes, uint32_t val)
-{
-    switch ( bytes )
-    {
-    case 1:
-        stdvga_outb(port, val);
-        break;
-
-    case 2:
-        stdvga_outb(port + 0, val >> 0);
-        stdvga_outb(port + 1, val >> 8);
-        break;
-
-    default:
-        break;
-    }
-}
-
-static int cf_check stdvga_intercept_pio(
-    int dir, unsigned int port, unsigned int bytes, uint32_t *val)
-{
-    struct hvm_hw_stdvga *s = &current->domain->arch.hvm.stdvga;
-
-    if ( dir == IOREQ_WRITE )
-    {
-        spin_lock(&s->lock);
-        stdvga_out(port, bytes, *val);
-        spin_unlock(&s->lock);
-    }
-
-    return X86EMUL_UNHANDLEABLE; /* propagate to external ioemu */
-}
-
 static int cf_check stdvga_mem_read(
     const struct hvm_io_handler *handler, uint64_t addr, uint32_t size,
     uint64_t *p_data)
@@ -195,11 +139,6 @@ void stdvga_init(struct domain *d)
     {
         struct hvm_io_handler *handler;
 
-        /* Sequencer registers. */
-        register_portio_handler(d, 0x3c4, 2, stdvga_intercept_pio);
-        /* Graphics registers. */
-        register_portio_handler(d, 0x3ce, 2, stdvga_intercept_pio);
-
         /* VGA memory */
         handler = hvm_next_io_handler(d);
 
diff --git a/xen/arch/x86/include/asm/hvm/io.h 
b/xen/arch/x86/include/asm/hvm/io.h
index d17cf20fd4..03a437fb8b 100644
--- a/xen/arch/x86/include/asm/hvm/io.h
+++ b/xen/arch/x86/include/asm/hvm/io.h
@@ -122,8 +122,6 @@ struct vpci_arch_msix_entry {
 };
 
 struct hvm_hw_stdvga {
-    uint8_t sr_index;
-    uint8_t gr_index;
     struct page_info *vram_page[64];  /* shadow of 0xa0000-0xaffff */
     spinlock_t lock;
 };
--
generated by git-patchbot for /home/xen/git/xen.git#staging-4.17