From 25b0dad541e31bd892d57cbeafe8e0c0bf4e8385 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Mon, 23 Apr 2018 11:01:09 +0200 Subject: [PATCH] x86/HVM: never retain emulated insn cache when exiting back to guest Commit 5fcb26e69e ("x86/HVM: don't retain emulated insn cache when exiting back to guest") didn't go quite far enough: The insn emulator may itself decide to return X86EMUL_RETRY (currently for certain CMPXCHG failures and AVX2 gather insns), in which case we'd also exit back to guest context. Tie the caching to whether we have an I/O completion pending, instead of x86_emulate()'s return value. Signed-off-by: Jan Beulich Reviewed-by: Paul Durrant Release-acked-by: Juergen Gross --- xen/arch/x86/hvm/emulate.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c index f8fca57254..c9aa18884d 100644 --- a/xen/arch/x86/hvm/emulate.c +++ b/xen/arch/x86/hvm/emulate.c @@ -2266,22 +2266,20 @@ static int _hvm_emulate_one(struct hvm_emulate_ctxt *hvmemul_ctxt, vio->mmio_retry = 0; - switch ( rc = x86_emulate(&hvmemul_ctxt->ctxt, ops) ) + rc = x86_emulate(&hvmemul_ctxt->ctxt, ops); + if ( rc == X86EMUL_OKAY && vio->mmio_retry ) + rc = X86EMUL_RETRY; + + if ( !hvm_vcpu_io_need_completion(vio) ) { - case X86EMUL_OKAY: - if ( vio->mmio_retry ) - rc = X86EMUL_RETRY; - /* fall through */ - default: vio->mmio_cache_count = 0; vio->mmio_insn_bytes = 0; - break; - - case X86EMUL_RETRY: + } + else + { BUILD_BUG_ON(sizeof(vio->mmio_insn) < sizeof(hvmemul_ctxt->insn_buf)); vio->mmio_insn_bytes = hvmemul_ctxt->insn_buf_bytes; memcpy(vio->mmio_insn, hvmemul_ctxt->insn_buf, vio->mmio_insn_bytes); - break; } if ( hvmemul_ctxt->ctxt.retire.singlestep ) -- 2.30.2