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MIPS: KVM: Don't hardcode restored HWREna 

KVM modifies CP0_HWREna during guest execution so it can trap and
emulate RDHWR instructions, however it always restores the hardcoded
value 0x2000000F. This assumes the presence of the UserLocal register,
and the absence of any implementation dependent or future HW registers.

Fix by exporting the value that traps.c write into CP0_HWREna, and
loading from there instead of hard coding.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
James Hogan 2016-06-15 19:29:53 +01:00 committed by Paolo Bonzini
parent aff565aab9
commit b937ff628f
3 changed files with 7 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/mips/include/asm/setup.h
View File

@ -21,6 +21,7 @@ extern void *set_vi_handler(int n, vi_handler_t addr);
extern void *set_except_vector(int n, void *addr);
extern unsigned long ebase;
extern unsigned int hwrena;
extern void per_cpu_trap_init(bool);
extern void cpu_cache_init(void);

5
arch/mips/kernel/traps.c
View File

@ -2064,10 +2064,13 @@ static void configure_status(void)
status_set);
}
unsigned int hwrena;
EXPORT_SYMBOL_GPL(hwrena);
/* configure HWRENA register */
static void configure_hwrena(void)
{
unsigned int hwrena = cpu_hwrena_impl_bits;
hwrena = cpu_hwrena_impl_bits;
if (cpu_has_mips_r2_r6)
hwrena |= MIPS_HWRENA_CPUNUM |

4
arch/mips/kvm/locore.S
View File

@ -381,7 +381,7 @@ NESTED (MIPSX(GuestException), CALLFRAME_SIZ, ra)
mtc0 k0, CP0_DDATA_LO
/* Restore RDHWR access */
PTR_LI k0, 0x2000000F
INT_L k0, hwrena
mtc0 k0, CP0_HWRENA
/* Jump to handler */
@ -553,7 +553,7 @@ __kvm_mips_return_to_host:
mtlo k0
/* Restore RDHWR access */
PTR_LI k0, 0x2000000F
INT_L k0, hwrena
mtc0 k0, CP0_HWRENA
/* Restore RA, which is the address we will return to */