[PATCH 02/21] MIPS: KVM: Use local_flush_icache_range to fix RI on XBurst

James Hogan
2014-04-25T15:19:45Z

MIPS KVM uses mips32_SyncICache to synchronise the icache with the
dcache after dynamically modifying guest instructions or writing guest
exception vector. However this uses rdhwr to get the SYNCI step, which
causes a reserved instruction exception on Ingenic XBurst cores.

It would seem to make more sense to use local_flush_icache_range()
instead which does the same thing but is more portable.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: kvm@vger.kernel.org
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: Sanjay Lal <sanjayl@kymasys.com>
---
arch/mips/include/asm/kvm_host.h | 1 -
arch/mips/kvm/kvm_locore.S | 32 --------------------------------
arch/mips/kvm/kvm_mips.c | 3 ++-
arch/mips/kvm/kvm_mips_dyntrans.c | 15 +++++++++------
arch/mips/kvm/kvm_mips_emul.c | 2 +-
5 files changed, 12 insertions(+), 41 deletions(-)

diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index 060aaa6348d7..f0e25c6d10b2 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -646,7 +646,6 @@ extern int kvm_mips_trans_mtc0(uint32_t inst, uint32_t *opc,
struct kvm_vcpu *vcpu);

/* Misc */
-extern void mips32_SyncICache(unsigned long addr, unsigned long size);
extern int kvm_mips_dump_stats(struct kvm_vcpu *vcpu);
extern unsigned long kvm_mips_get_ramsize(struct kvm *kvm);

diff --git a/arch/mips/kvm/kvm_locore.S b/arch/mips/kvm/kvm_locore.S
index bbace092ad0a..033ac343e72c 100644
--- a/arch/mips/kvm/kvm_locore.S
+++ b/arch/mips/kvm/kvm_locore.S
@@ -611,35 +611,3 @@ MIPSX(exceptions):
.word _C_LABEL(MIPSX(GuestException)) # 29
.word _C_LABEL(MIPSX(GuestException)) # 30
.word _C_LABEL(MIPSX(GuestException)) # 31
-
-
-/* This routine makes changes to the instruction stream effective to the hardware.
- * It should be called after the instruction stream is written.
- * On return, the new instructions are effective.
- * Inputs:
- * a0 = Start address of new instruction stream
- * a1 = Size, in bytes, of new instruction stream
- */
-
-#define HW_SYNCI_Step $1
-LEAF(MIPSX(SyncICache))
- .set push
- .set mips32r2
- beq a1, zero, 20f
- nop
- REG_ADDU a1, a0, a1
- rdhwr v0, HW_SYNCI_Step
- beq v0, zero, 20f
- nop
-10:
- synci 0(a0)
- REG_ADDU a0, a0, v0
- sltu v1, a0, a1
- bne v1, zero, 10b
- nop
- sync
-20:
- jr.hb ra
- nop
- .set pop
-END(MIPSX(SyncICache))
diff --git a/arch/mips/kvm/kvm_mips.c b/arch/mips/kvm/kvm_mips.c
index 5efce56f0df0..14511138f187 100644
--- a/arch/mips/kvm/kvm_mips.c
+++ b/arch/mips/kvm/kvm_mips.c
@@ -350,7 +350,8 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
mips32_GuestExceptionEnd - mips32_GuestException);

/* Invalidate the icache for these ranges */
- mips32_SyncICache((unsigned long) gebase, ALIGN(size, PAGE_SIZE));
+ local_flush_icache_range((unsigned long)gebase,
+ (unsigned long)gebase + ALIGN(size, PAGE_SIZE));

/* Allocate comm page for guest kernel, a TLB will be reserved for mapping GVA @ 0xFFFF8000 to this page */
vcpu->arch.kseg0_commpage = kzalloc(PAGE_SIZE << 1, GFP_KERNEL);
diff --git a/arch/mips/kvm/kvm_mips_dyntrans.c b/arch/mips/kvm/kvm_mips_dyntrans.c
index 96528e2d1ea6..b80e41d858fd 100644
--- a/arch/mips/kvm/kvm_mips_dyntrans.c
+++ b/arch/mips/kvm/kvm_mips_dyntrans.c
@@ -16,6 +16,7 @@
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <linux/bootmem.h>
+#include <asm/cacheflush.h>

#include "kvm_mips_comm.h"

@@ -40,7 +41,7 @@ kvm_mips_trans_cache_index(uint32_t inst, uint32_t *opc,
CKSEG0ADDR(kvm_mips_translate_guest_kseg0_to_hpa
(vcpu, (unsigned long) opc));
memcpy((void *)kseg0_opc, (void *)&synci_inst, sizeof(uint32_t));
- mips32_SyncICache(kseg0_opc, 32);
+ local_flush_icache_range(kseg0_opc, kseg0_opc + 32);

return result;
}
@@ -66,7 +67,7 @@ kvm_mips_trans_cache_va(uint32_t inst, uint32_t *opc,
CKSEG0ADDR(kvm_mips_translate_guest_kseg0_to_hpa
(vcpu, (unsigned long) opc));
memcpy((void *)kseg0_opc, (void *)&synci_inst, sizeof(uint32_t));
- mips32_SyncICache(kseg0_opc, 32);
+ local_flush_icache_range(kseg0_opc, kseg0_opc + 32);

return result;
}
@@ -99,11 +100,12 @@ kvm_mips_trans_mfc0(uint32_t inst, uint32_t *opc, struct kvm_vcpu *vcpu)
CKSEG0ADDR(kvm_mips_translate_guest_kseg0_to_hpa
(vcpu, (unsigned long) opc));
memcpy((void *)kseg0_opc, (void *)&mfc0_inst, sizeof(uint32_t));
- mips32_SyncICache(kseg0_opc, 32);
+ local_flush_icache_range(kseg0_opc, kseg0_opc + 32);
} else if (KVM_GUEST_KSEGX((unsigned long) opc) == KVM_GUEST_KSEG23) {
local_irq_save(flags);
memcpy((void *)opc, (void *)&mfc0_inst, sizeof(uint32_t));
- mips32_SyncICache((unsigned long) opc, 32);
+ local_flush_icache_range((unsigned long)opc,
+ (unsigned long)opc + 32);
local_irq_restore(flags);
} else {
kvm_err("%s: Invalid address: %p\n", __func__, opc);
@@ -134,11 +136,12 @@ kvm_mips_trans_mtc0(uint32_t inst, uint32_t *opc, struct kvm_vcpu *vcpu)
CKSEG0ADDR(kvm_mips_translate_guest_kseg0_to_hpa
(vcpu, (unsigned long) opc));
memcpy((void *)kseg0_opc, (void *)&mtc0_inst, sizeof(uint32_t));
- mips32_SyncICache(kseg0_opc, 32);
+ local_flush_icache_range(kseg0_opc, kseg0_opc + 32);
} else if (KVM_GUEST_KSEGX((unsigned long) opc) == KVM_GUEST_KSEG23) {
local_irq_save(flags);
memcpy((void *)opc, (void *)&mtc0_inst, sizeof(uint32_t));
- mips32_SyncICache((unsigned long) opc, 32);
+ local_flush_icache_range((unsigned long)opc,
+ (unsigned long)opc + 32);
local_irq_restore(flags);
} else {
kvm_err("%s: Invalid address: %p\n", __func__, opc);
diff --git a/arch/mips/kvm/kvm_mips_emul.c b/arch/mips/kvm/kvm_mips_emul.c
index e3fec99941a7..bad31c6235d4 100644
--- a/arch/mips/kvm/kvm_mips_emul.c
+++ b/arch/mips/kvm/kvm_mips_emul.c
@@ -887,7 +887,7 @@ int kvm_mips_sync_icache(unsigned long va, struct kvm_vcpu *vcpu)

printk("%s: va: %#lx, unmapped: %#x\n", __func__, va, CKSEG0ADDR(pa));

- mips32_SyncICache(CKSEG0ADDR(pa), 32);
+ local_flush_icache_range(CKSEG0ADDR(pa), 32);
return 0;
}

--
1.8.1.2