renegade-project/linux-next
2
0
Fork 0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-16 17:23:55 +08:00
Code

KVM guest: Make pv trampoline code executable

Browse Source 
Our PV guest patching code assembles chunks of instructions on the fly when it
encounters more complicated instructions to hijack. These instructions need
to live in a section that we don't mark as non-executable, as otherwise we
fault when jumping there.

Right now we put it into the .bss section where it automatically gets marked
as non-executable. Add a check to the NX setting function to ensure that we
leave these particular pages executable.

Signed-off-by: Alexander Graf <agraf@suse.de>
This commit is contained in:
Alexander Graf 2014-04-29 12:17:26 +02:00
parent ab78475c76
commit b18db0b808
3 changed files with 16 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
arch/powerpc/include/asm/sections.h
View File

@ -39,6 +39,17 @@ static inline int overlaps_kernel_text(unsigned long start, unsigned long end)
(unsigned long)_stext < end;
}
static inline int overlaps_kvm_tmp(unsigned long start, unsigned long end)
{
#ifdef CONFIG_KVM_GUEST
extern char kvm_tmp[];
return start < (unsigned long)kvm_tmp &&
(unsigned long)&kvm_tmp[1024 * 1024] < end;
#else
return 0;
#endif
}
#undef dereference_function_descriptor
static inline void *dereference_function_descriptor(void *ptr)
{

2
arch/powerpc/kernel/kvm.c
View File

@ -74,7 +74,7 @@
#define KVM_INST_MTSRIN 0x7c0001e4
static bool kvm_patching_worked = true;
static char kvm_tmp[1024 * 1024];
char kvm_tmp[1024 * 1024];
static int kvm_tmp_index;
static inline void kvm_patch_ins(u32 *inst, u32 new_inst)

4
arch/powerpc/mm/hash_utils_64.c
View File

@ -207,6 +207,10 @@ int htab_bolt_mapping(unsigned long vstart, unsigned long vend,
if (overlaps_kernel_text(vaddr, vaddr + step))
tprot &= ~HPTE_R_N;
/* Make kvm guest trampolines executable */
if (overlaps_kvm_tmp(vaddr, vaddr + step))
tprot &= ~HPTE_R_N;
/*
* If relocatable, check if it overlaps interrupt vectors that
* are copied down to real 0. For relocatable kernel