diff mbox

[09/17] MIPS: KVM: Don't hardcode restored HWREna

Message ID 1466015401-24433-10-git-send-email-james.hogan@imgtec.com (mailing list archive)
State New, archived
Headers show

Commit Message

James Hogan June 15, 2016, 6:29 p.m. UTC 
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>
Cc: 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
---
 arch/mips/include/asm/setup.h | 1 +
 arch/mips/kernel/traps.c      | 5 ++++-
 arch/mips/kvm/locore.S        | 4 ++--
 3 files changed, 7 insertions(+), 3 deletions(-)

Comments

Ralf Baechle June 15, 2016, 9:50 p.m. UTC | #1 
Acked-by: Ralf Baechle <ralf@linux-mips.org>
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diff mbox

Patch

diff --git a/arch/mips/include/asm/setup.h b/arch/mips/include/asm/setup.h
index d7bfdeba9e84..4f5279a8308d 100644
--- a/arch/mips/include/asm/setup.h
+++ b/arch/mips/include/asm/setup.h
@@ -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);
 
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 7176a6057e26..6fb4704bd156 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -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 |
diff --git a/arch/mips/kvm/locore.S b/arch/mips/kvm/locore.S
index f87bec546366..698286c0f732 100644
--- a/arch/mips/kvm/locore.S
+++ b/arch/mips/kvm/locore.S
@@ -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 */