On 11/05/2017 09:00, Miltiadis Hatzimihail wrote:
>
> The interesting thing is that in the ram case the test is passing, but in
> the io is failing. Also, if I try this without KVM, it passes in both cases.
Yes, in the RAM case KVM is not invoked at all.
> So I ve done some reading and for the 2 cases above I get:
>
> - KVM_EXIT_MMIO on memory_region_init_io (KVM attempts and fails to
> emulate MOVSS),
> - KVM_EXIT_EXCEPTION on memory_region_init_ram(QEMU emulates MOVSS)
No, you don't get any exit for memory_region_init_ram.
> Is that right?
>
> Now the question is, if I want to use the IO instead of a RAM, what's the
> best way to solve this?
Please try this KVM patch:
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index c25cfaf584e7..53fbd1589d2e 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3534,6 +3534,22 @@ static int em_rdpmc(struct x86_emulate_ctxt *ctxt)
return X86EMUL_CONTINUE;
}
+static int em_movss(struct x86_emulate_ctxt *ctxt)
+{
+ memcpy(ctxt->dst.valptr, ctxt->src.valptr, 4);
+ ctxt->op_bytes = 4;
+ ctxt->dst.bytes = 4;
+ return X86EMUL_CONTINUE;
+}
+
+static int em_movsd(struct x86_emulate_ctxt *ctxt)
+{
+ memcpy(ctxt->dst.valptr, ctxt->src.valptr, 8);
+ ctxt->op_bytes = 8;
+ ctxt->dst.bytes = 8;
+ return X86EMUL_CONTINUE;
+}
+
static int em_mov(struct x86_emulate_ctxt *ctxt)
{
memcpy(ctxt->dst.valptr, ctxt->src.valptr, sizeof(ctxt->src.valptr));
@@ -4407,6 +4423,11 @@ static int check_perm_out(struct x86_emulate_ctxt *ctxt)
I(Mmx, em_mov), I(Sse | Aligned, em_mov), N, I(Sse | Unaligned, em_mov),
};
+static const struct gprefix pfx_0f_10_0f_11 = {
+ I(Sse | Unaligned, em_mov), I(Sse | Unaligned, em_mov),
+ I(Sse, em_movsd), I(Sse, em_movss),
+};
+
static const struct instr_dual instr_dual_0f_2b = {
I(0, em_mov), N
};
@@ -4626,6 +4647,8 @@ static int check_perm_out(struct x86_emulate_ctxt *ctxt)
DI(ImplicitOps | Priv, invd), DI(ImplicitOps | Priv, wbinvd), N, N,
N, D(ImplicitOps | ModRM | SrcMem | NoAccess), N, N,
/* 0x10 - 0x1F */
+ GP(SrcMem | DstReg | ModRM | Mov, &pfx_0f_10_0f_11),
+ GP(SrcReg | DstMem | ModRM | Mov, &pfx_0f_10_0f_11),
N, N, N, N, N, N, N, N,
D(ImplicitOps | ModRM | SrcMem | NoAccess),
N, N, N, N, N, N, D(ImplicitOps | ModRM | SrcMem | NoAccess),
Thanks,
Paolo
