MMIO emulation reads the last instruction executed by the guest
and then emulates. If the guest is running in Little Endian mode,
the instruction needs to be byte-swapped before being emulated.
This patch stores the last instruction in the endian order of the
host, primarily doing a byte-swap if needed. The common code
which fetches 'last_inst' uses a helper routine kvmppc_need_byteswap().
and the exit paths for the Book3S PV and HR guests use their own
version in assembly.
Finally, kvmppc_emulate_instruction() uses kvmppc_is_bigendian()
to define in which endian order the mmio needs to be done.
Signed-off-by: Cédric Le Goater <clg@xxxxxxxxxx>
---
arch/powerpc/include/asm/kvm_book3s.h | 9 +++-
arch/powerpc/kvm/book3s_hv_rmhandlers.S | 12 ++++++
arch/powerpc/kvm/book3s_segment.S | 11 +++++
arch/powerpc/kvm/emulate.c | 72 +++++++++++++++++--------------
4 files changed, 71 insertions(+), 33 deletions(-)
diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index 00c2061..9c2b865 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -289,7 +289,14 @@ static inline int kvmppc_ld32(struct kvm_vcpu *vcpu, ulong *eaddr,
static inline int kvmppc_ld_inst(struct kvm_vcpu *vcpu, ulong *eaddr,
u32 *inst)
{
- return kvmppc_ld32(vcpu, eaddr, inst, false);
+ int ret;
+
+ ret = kvmppc_ld32(vcpu, eaddr, inst, false);
+
+ if (kvmppc_need_byteswap(vcpu))
+ *inst = swab32(*inst);
+
+ return ret;
}
static inline u32 kvmppc_get_last_inst(struct kvm_vcpu *vcpu)
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 77f1baa..7c9978a 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -1404,10 +1404,22 @@ fast_interrupt_c_return:
lwz r8, 0(r10)
mtmsrd r3
+ ld r0, VCPU_MSR(r9)
+
+ /* r10 = vcpu->arch.msr & MSR_LE */
+ rldicl. r10, r0, 0, 63
+
/* Store the result */
stw r8, VCPU_LAST_INST(r9)
+ beq after_inst_store
+
+ /* Swap and store the result */
+ addi r11, r9, VCPU_LAST_INST
+ stwbrx r8, 0, r11
+
/* Unset guest mode. */
+after_inst_store:
li r0, KVM_GUEST_MODE_HOST_HV
stb r0, HSTATE_IN_GUEST(r13)
b guest_exit_cont
diff --git a/arch/powerpc/kvm/book3s_segment.S b/arch/powerpc/kvm/book3s_segment.S
index 1abe478..2ceed4c 100644
--- a/arch/powerpc/kvm/book3s_segment.S
+++ b/arch/powerpc/kvm/book3s_segment.S
@@ -287,8 +287,19 @@ ld_last_inst:
sync
#endif
+ ld r8, SVCPU_SHADOW_SRR1(r13)
+
+ /* r10 = vcpu->arch.msr & MSR_LE */
+ rldicl. r10, r8, 0, 63
+
stw r0, SVCPU_LAST_INST(r13)
+ beq no_ld_last_inst
+
+ /* swap and store the result */
+ addi r11, r13, SVCPU_LAST_INST
+ stwbrx r0, 0, r11
+
no_ld_last_inst:
/* Unset guest mode */
diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
index 751cd45..76d0a12 100644
--- a/arch/powerpc/kvm/emulate.c
+++ b/arch/powerpc/kvm/emulate.c
@@ -219,7 +219,6 @@ static int kvmppc_emulate_mfspr(struct kvm_vcpu *vcpu, int sprn, int rt)
* lmw
* stmw
*
- * XXX is_bigendian should depend on MMU mapping or MSR[LE]
*/
/* XXX Should probably auto-generate instruction decoding for a particular core
* from opcode tables in the future. */
@@ -232,6 +231,7 @@ int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
int sprn = get_sprn(inst);
enum emulation_result emulated = EMULATE_DONE;
int advance = 1;
+ int is_bigendian = kvmppc_is_bigendian(vcpu);
/* this default type might be overwritten by subcategories */
kvmppc_set_exit_type(vcpu, EMULATED_INST_EXITS);
@@ -266,47 +266,53 @@ int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
advance = 0;
break;
case OP_31_XOP_LWZX:
- emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
+ emulated = kvmppc_handle_load(run, vcpu, rt, 4,
+ is_bigendian);
break;
case OP_31_XOP_LBZX:
- emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
+ emulated = kvmppc_handle_load(run, vcpu, rt, 1,
+ is_bigendian);
break;
case OP_31_XOP_LBZUX:
- emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
+ emulated = kvmppc_handle_load(run, vcpu, rt, 1,
+ is_bigendian);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_31_XOP_STWX:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
- 4, 1);
+ 4, is_bigendian);
break;
case OP_31_XOP_STBX:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
- 1, 1);
+ 1, is_bigendian);
break;
case OP_31_XOP_STBUX:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
- 1, 1);
+ 1, is_bigendian);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_31_XOP_LHAX:
- emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
+ emulated = kvmppc_handle_loads(run, vcpu, rt, 2,
+ is_bigendian);
break;
case OP_31_XOP_LHZX:
- emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
+ emulated = kvmppc_handle_load(run, vcpu, rt, 2,
+ is_bigendian);
break;
case OP_31_XOP_LHZUX:
- emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
+ emulated = kvmppc_handle_load(run, vcpu, rt, 2,
+ is_bigendian);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
@@ -317,13 +323,13 @@ int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
case OP_31_XOP_STHX:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
- 2, 1);
+ 2, is_bigendian);
break;
case OP_31_XOP_STHUX:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
- 2, 1);
+ 2, is_bigendian);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
@@ -342,7 +348,8 @@ int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
break;
case OP_31_XOP_LWBRX:
- emulated = kvmppc_handle_load(run, vcpu, rt, 4, 0);
+ emulated = kvmppc_handle_load(run, vcpu, rt, 4,
+ !is_bigendian);
break;
case OP_31_XOP_TLBSYNC:
@@ -351,17 +358,18 @@ int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
case OP_31_XOP_STWBRX:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
- 4, 0);
+ 4, !is_bigendian);
break;
case OP_31_XOP_LHBRX:
- emulated = kvmppc_handle_load(run, vcpu, rt, 2, 0);
+ emulated = kvmppc_handle_load(run, vcpu, rt, 2,
+ !is_bigendian);
break;
case OP_31_XOP_STHBRX:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
- 2, 0);
+ 2, !is_bigendian);
break;
default:
@@ -371,33 +379,33 @@ int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
break;
case OP_LWZ:
- emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
+ emulated = kvmppc_handle_load(run, vcpu, rt, 4, is_bigendian);
break;
/* TBD: Add support for other 64 bit load variants like ldu, ldux, ldx etc. */
case OP_LD:
rt = get_rt(inst);
- emulated = kvmppc_handle_load(run, vcpu, rt, 8, 1);
+ emulated = kvmppc_handle_load(run, vcpu, rt, 8, is_bigendian);
break;
case OP_LWZU:
- emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
+ emulated = kvmppc_handle_load(run, vcpu, rt, 4, is_bigendian);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_LBZ:
- emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
+ emulated = kvmppc_handle_load(run, vcpu, rt, 1, is_bigendian);
break;
case OP_LBZU:
- emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
+ emulated = kvmppc_handle_load(run, vcpu, rt, 1, is_bigendian);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_STW:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
- 4, 1);
+ 4, is_bigendian);
break;
/* TBD: Add support for other 64 bit store variants like stdu, stdux, stdx etc. */
@@ -405,57 +413,57 @@ int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
rs = get_rs(inst);
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
- 8, 1);
+ 8, is_bigendian);
break;
case OP_STWU:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
- 4, 1);
+ 4, is_bigendian);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_STB:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
- 1, 1);
+ 1, is_bigendian);
break;
case OP_STBU:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
- 1, 1);
+ 1, is_bigendian);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_LHZ:
- emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
+ emulated = kvmppc_handle_load(run, vcpu, rt, 2, is_bigendian);
break;
case OP_LHZU:
- emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
+ emulated = kvmppc_handle_load(run, vcpu, rt, 2, is_bigendian);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_LHA:
- emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
+ emulated = kvmppc_handle_loads(run, vcpu, rt, 2, is_bigendian);
break;
case OP_LHAU:
- emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
+ emulated = kvmppc_handle_loads(run, vcpu, rt, 2, is_bigendian);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_STH:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
- 2, 1);
+ 2, is_bigendian);
break;
case OP_STHU:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
- 2, 1);
+ 2, is_bigendian);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
--
1.7.10.4
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