From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x226TfqMeJoIuQZzzm+zOdi/JUjDU+aMjzZ23o7vKTvhFdDh59uk2ExrU3PwBDbg4f137EWgZ ARC-Seal: i=1; a=rsa-sha256; t=1517591011; cv=none; d=google.com; s=arc-20160816; b=C0pX74SizLT4/QLu1b9On4zarD+fKfzMTHJzcxnpmAruJ0BusNFW1+aCWyNfOnPr5h M37MTQUXOL6HPWFC7Exjb40hpWawU7t+EBDgqrHFCUdHmgFgdQ6p+VmrtMJRDRpT7Uqr BHwwUUAjgtYoP1g8pVNkpOvJi7iNi7V03az7LwFQmjtYp2CNWnEtZJ0fSe2OueRgsayb jqg3YHdg7nAyQWDwf46UrvscVMVzSYSg+wpbdeNyBLOgxS4YcAQgVughfsCG6usR0puo WwxtIZaWQZD2vzYG/NE12IhSyyVShFDr9fTyTiql2/T9oj/6VyYzYlRLSh25RZZdI/9P mT6g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=JQknGv75E+CPWwz0sCAD+2jk2NNafuoE92G91a7FEzE=; b=077+luSiNS5CooBHxT2d6WRyCToQZWn6eXvjbfuDIacej1hghGZ+3UH0AdoMspta0r rnFozZcNZjWNHdnazmM9dFLicr8pzYoO1qtElOhMzp/4jYtaVSTJbCsAlBN7kBtftXr/ 8kP0UIVW16MfW3ZGtepuVlLXeH4FZ2Kt4IyZi1rJ85/fJ+h6l0mR9CjP31y3rKoLXdv4 pYhCQy6IagbIWgQ/lWtLQwjbPEsR+/akG3MdTvt8UtzvbTase1CLg6m7WUpW4itYCbM0 h9i93kUo5E1K3cMCQcxQ2gw0mH6H19QZSi711k0PzxSDZuPE2uZ0SK3BQBf/ftWePnks HQ6g== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Pedro Fonseca , Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Nadav Amit , Wanpeng Li , Sasha Levin Subject: [PATCH 4.9 22/86] KVM: X86: Fix operand/address-size during instruction decoding Date: Fri, 2 Feb 2018 17:57:42 +0100 Message-Id: <20180202140824.743794349@linuxfoundation.org> X-Mailer: git-send-email 2.16.1 In-Reply-To: <20180202140822.679101338@linuxfoundation.org> References: <20180202140822.679101338@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1591309309879638297?= X-GMAIL-MSGID: =?utf-8?q?1591309511910518492?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Wanpeng Li [ Upstream commit 3853be2603191829b442b64dac6ae8ba0c027bf9 ] Pedro reported: During tests that we conducted on KVM, we noticed that executing a "PUSH %ES" instruction under KVM produces different results on both memory and the SP register depending on whether EPT support is enabled. With EPT the SP is reduced by 4 bytes (and the written value is 0-padded) but without EPT support it is only reduced by 2 bytes. The difference can be observed when the CS.DB field is 1 (32-bit) but not when it's 0 (16-bit). The internal segment descriptor cache exist even in real/vm8096 mode. The CS.D also should be respected instead of just default operand/address-size/66H prefix/67H prefix during instruction decoding. This patch fixes it by also adjusting operand/address-size according to CS.D. Reported-by: Pedro Fonseca Tested-by: Pedro Fonseca Cc: Paolo Bonzini Cc: Radim Krčmář Cc: Nadav Amit Cc: Pedro Fonseca Signed-off-by: Wanpeng Li Reviewed-by: Paolo Bonzini Signed-off-by: Radim Krčmář Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/emulate.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -4990,6 +4990,8 @@ int x86_decode_insn(struct x86_emulate_c bool op_prefix = false; bool has_seg_override = false; struct opcode opcode; + u16 dummy; + struct desc_struct desc; ctxt->memop.type = OP_NONE; ctxt->memopp = NULL; @@ -5008,6 +5010,11 @@ int x86_decode_insn(struct x86_emulate_c switch (mode) { case X86EMUL_MODE_REAL: case X86EMUL_MODE_VM86: + def_op_bytes = def_ad_bytes = 2; + ctxt->ops->get_segment(ctxt, &dummy, &desc, NULL, VCPU_SREG_CS); + if (desc.d) + def_op_bytes = def_ad_bytes = 4; + break; case X86EMUL_MODE_PROT16: def_op_bytes = def_ad_bytes = 2; break;