From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3B2DFC433DB for ; Thu, 18 Feb 2021 16:15:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E0C9964EAD for ; Thu, 18 Feb 2021 16:15:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233272AbhBRQOi (ORCPT ); Thu, 18 Feb 2021 11:14:38 -0500 Received: from foss.arm.com ([217.140.110.172]:51530 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233306AbhBROHV (ORCPT ); Thu, 18 Feb 2021 09:07:21 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1BD3FED1; Thu, 18 Feb 2021 06:06:28 -0800 (PST) Received: from slackpad.fritz.box (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E17B53F73B; Thu, 18 Feb 2021 06:06:26 -0800 (PST) Date: Thu, 18 Feb 2021 14:05:29 +0000 From: Andre Przywara To: Alexandru Elisei Cc: Will Deacon , Julien Thierry , kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, Marc Zyngier Subject: Re: [PATCH kvmtool 09/21] x86/ioport: Switch to new trap handlers Message-ID: <20210218140529.1d23c397@slackpad.fritz.box> In-Reply-To: References: <20201210142908.169597-1-andre.przywara@arm.com> <20201210142908.169597-10-andre.przywara@arm.com> Organization: Arm Ltd. X-Mailer: Claws Mail 3.17.1 (GTK+ 2.24.31; x86_64-slackware-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Fri, 12 Feb 2021 11:27:59 +0000 Alexandru Elisei wrote: Hi Alex, > On 12/10/20 2:28 PM, Andre Przywara wrote: > > Now that the x86 I/O ports have trap handlers adhering to the MMIO fault > > handler prototype, let's switch over to the joint registration routine. > > > > This allows us to get rid of the ioport shim routines. > > > > Signed-off-by: Andre Przywara > > --- > > x86/ioport.c | 113 ++++++++++++++------------------------------------- > > 1 file changed, 30 insertions(+), 83 deletions(-) > > > > diff --git a/x86/ioport.c b/x86/ioport.c > > index 932da20a..87955da1 100644 > > --- a/x86/ioport.c > > +++ b/x86/ioport.c > > @@ -8,16 +8,6 @@ static void dummy_mmio(struct kvm_cpu *vcpu, u64 addr, u8 *data, u32 len, > > { > > } > > > > -static bool debug_io_out(struct ioport *ioport, struct kvm_cpu *vcpu, u16 port, void *data, int size) > > -{ > > - dummy_mmio(vcpu, port, data, size, true, NULL); > > - return 0; > > -} > > 0 is false in boolean logic, which means that emulation fails according to the > (old) ioport emulation code (ioport.c::kvm__emulate_io()). > > So I guess I have a few questions: > > - Is this a bug in the emulation code, where the author thought that > debug_io_out() returns an int, and in that case 0 actually means success? Wading through the swamp of the git history it looks like failure is intentional, it should be used together with --debug-ioport, to trigger that print there. > - If writing to the debug port is rightfully considered an error, do we care > enough about it to print something to stdout like kvm__emulate_io() does when > debug_io_out() returns false? I think you are right, we should print something here. Cheers, Andre > > - > > -static struct ioport_operations debug_ops = { > > - .io_out = debug_io_out, > > -}; > > - > > static void seabios_debug_mmio(struct kvm_cpu *vcpu, u64 addr, u8 *data, > > u32 len, u8 is_write, void *ptr) > > { > > @@ -31,37 +21,6 @@ static void seabios_debug_mmio(struct kvm_cpu *vcpu, u64 addr, u8 *data, > > putchar(ch); > > } > > > > -static bool seabios_debug_io_out(struct ioport *ioport, struct kvm_cpu *vcpu, u16 port, void *data, int size) > > -{ > > - seabios_debug_mmio(vcpu, port, data, size, true, NULL); > > - return 0; > > -} > > - > > -static struct ioport_operations seabios_debug_ops = { > > - .io_out = seabios_debug_io_out, > > -}; > > - > > -static bool dummy_io_in(struct ioport *ioport, struct kvm_cpu *vcpu, u16 port, void *data, int size) > > -{ > > - dummy_mmio(vcpu, port, data, size, false, NULL); > > - return true; > > -} > > - > > -static bool dummy_io_out(struct ioport *ioport, struct kvm_cpu *vcpu, u16 port, void *data, int size) > > -{ > > - dummy_mmio(vcpu, port, data, size, true, NULL); > > - return true; > > -} > > - > > -static struct ioport_operations dummy_read_write_ioport_ops = { > > - .io_in = dummy_io_in, > > - .io_out = dummy_io_out, > > -}; > > - > > -static struct ioport_operations dummy_write_only_ioport_ops = { > > - .io_out = dummy_io_out, > > -}; > > - > > /* > > * The "fast A20 gate" > > */ > > @@ -76,17 +35,6 @@ static void ps2_control_mmio(struct kvm_cpu *vcpu, u64 addr, u8 *data, u32 len, > > ioport__write8(data, 0x02); > > } > > > > -static bool ps2_control_a_io_in(struct ioport *ioport, struct kvm_cpu *vcpu, u16 port, void *data, int size) > > -{ > > - ps2_control_mmio(vcpu, port, data, size, false, NULL); > > - return true; > > -} > > - > > -static struct ioport_operations ps2_control_a_ops = { > > - .io_in = ps2_control_a_io_in, > > - .io_out = dummy_io_out, > > -}; > > - > > void ioport__map_irq(u8 *irq) > > { > > } > > @@ -98,75 +46,75 @@ static int ioport__setup_arch(struct kvm *kvm) > > /* Legacy ioport setup */ > > > > /* 0000 - 001F - DMA1 controller */ > > - r = ioport__register(kvm, 0x0000, &dummy_read_write_ioport_ops, 32, NULL); > > + r = kvm__register_pio(kvm, 0x0000, 32, dummy_mmio, NULL); > > if (r < 0) > > return r; > > > > /* 0x0020 - 0x003F - 8259A PIC 1 */ > > - r = ioport__register(kvm, 0x0020, &dummy_read_write_ioport_ops, 2, NULL); > > + r = kvm__register_pio(kvm, 0x0020, 2, dummy_mmio, NULL); > > if (r < 0) > > return r; > > > > /* PORT 0040-005F - PIT - PROGRAMMABLE INTERVAL TIMER (8253, 8254) */ > > - r = ioport__register(kvm, 0x0040, &dummy_read_write_ioport_ops, 4, NULL); > > + r = kvm__register_pio(kvm, 0x0040, 4, dummy_mmio, NULL); > > if (r < 0) > > return r; > > > > /* 0092 - PS/2 system control port A */ > > - r = ioport__register(kvm, 0x0092, &ps2_control_a_ops, 1, NULL); > > + r = kvm__register_pio(kvm, 0x0092, 1, ps2_control_mmio, NULL); > > if (r < 0) > > return r; > > > > /* 0x00A0 - 0x00AF - 8259A PIC 2 */ > > - r = ioport__register(kvm, 0x00A0, &dummy_read_write_ioport_ops, 2, NULL); > > + r = kvm__register_pio(kvm, 0x00A0, 2, dummy_mmio, NULL); > > if (r < 0) > > return r; > > > > /* 00C0 - 001F - DMA2 controller */ > > - r = ioport__register(kvm, 0x00C0, &dummy_read_write_ioport_ops, 32, NULL); > > + r = kvm__register_pio(kvm, 0x00c0, 32, dummy_mmio, NULL); > > if (r < 0) > > return r; > > > > /* PORT 00E0-00EF are 'motherboard specific' so we use them for our > > internal debugging purposes. */ > > - r = ioport__register(kvm, IOPORT_DBG, &debug_ops, 1, NULL); > > + r = kvm__register_pio(kvm, IOPORT_DBG, 1, dummy_mmio, NULL); > > if (r < 0) > > return r; > > > > /* PORT 00ED - DUMMY PORT FOR DELAY??? */ > > - r = ioport__register(kvm, 0x00ED, &dummy_write_only_ioport_ops, 1, NULL); > > + r = kvm__register_pio(kvm, 0x00ed, 1, dummy_mmio, NULL); > > if (r < 0) > > return r; > > > > /* 0x00F0 - 0x00FF - Math co-processor */ > > - r = ioport__register(kvm, 0x00F0, &dummy_write_only_ioport_ops, 2, NULL); > > + r = kvm__register_pio(kvm, 0x00f0, 2, dummy_mmio, NULL); > > if (r < 0) > > return r; > > > > /* PORT 0278-027A - PARALLEL PRINTER PORT (usually LPT1, sometimes LPT2) */ > > - r = ioport__register(kvm, 0x0278, &dummy_read_write_ioport_ops, 3, NULL); > > + r = kvm__register_pio(kvm, 0x0278, 3, dummy_mmio, NULL); > > if (r < 0) > > return r; > > > > /* PORT 0378-037A - PARALLEL PRINTER PORT (usually LPT2, sometimes LPT3) */ > > - r = ioport__register(kvm, 0x0378, &dummy_read_write_ioport_ops, 3, NULL); > > + r = kvm__register_pio(kvm, 0x0378, 3, dummy_mmio, NULL); > > if (r < 0) > > return r; > > > > /* PORT 03D4-03D5 - COLOR VIDEO - CRT CONTROL REGISTERS */ > > - r = ioport__register(kvm, 0x03D4, &dummy_read_write_ioport_ops, 1, NULL); > > + r = kvm__register_pio(kvm, 0x03d4, 1, dummy_mmio, NULL); > > if (r < 0) > > return r; > > - r = ioport__register(kvm, 0x03D5, &dummy_write_only_ioport_ops, 1, NULL); > > + r = kvm__register_pio(kvm, 0x03d5, 1, dummy_mmio, NULL); > > if (r < 0) > > return r; > > > > - r = ioport__register(kvm, 0x402, &seabios_debug_ops, 1, NULL); > > + r = kvm__register_pio(kvm, 0x0402, 1, seabios_debug_mmio, NULL); > > if (r < 0) > > return r; > > > > /* 0510 - QEMU BIOS configuration register */ > > - r = ioport__register(kvm, 0x510, &dummy_read_write_ioport_ops, 2, NULL); > > + r = kvm__register_pio(kvm, 0x0510, 2, dummy_mmio, NULL); > > if (r < 0) > > return r; > > > > @@ -176,22 +124,21 @@ dev_base_init(ioport__setup_arch); > > > > static int ioport__remove_arch(struct kvm *kvm) > > { > > - ioport__unregister(kvm, 0x510); > > - ioport__unregister(kvm, 0x402); > > - ioport__unregister(kvm, 0x03D5); > > - ioport__unregister(kvm, 0x03D4); > > - ioport__unregister(kvm, 0x0378); > > - ioport__unregister(kvm, 0x0278); > > - ioport__unregister(kvm, 0x00F0); > > - ioport__unregister(kvm, 0x00ED); > > - ioport__unregister(kvm, IOPORT_DBG); > > - ioport__unregister(kvm, 0x00C0); > > - ioport__unregister(kvm, 0x00A0); > > - ioport__unregister(kvm, 0x0092); > > - ioport__unregister(kvm, 0x0040); > > - ioport__unregister(kvm, 0x0020); > > - ioport__unregister(kvm, 0x0000); > > - > > + kvm__deregister_pio(kvm, 0x510); > > + kvm__deregister_pio(kvm, 0x402); > > + kvm__deregister_pio(kvm, 0x3d5); > > + kvm__deregister_pio(kvm, 0x3d4); > > + kvm__deregister_pio(kvm, 0x378); > > + kvm__deregister_pio(kvm, 0x278); > > + kvm__deregister_pio(kvm, 0x0f0); > > + kvm__deregister_pio(kvm, 0x0ed); > > + kvm__deregister_pio(kvm, IOPORT_DBG); > > + kvm__deregister_pio(kvm, 0x0c0); > > + kvm__deregister_pio(kvm, 0x0a0); > > + kvm__deregister_pio(kvm, 0x092); > > + kvm__deregister_pio(kvm, 0x040); > > + kvm__deregister_pio(kvm, 0x020); > > + kvm__deregister_pio(kvm, 0x000); > > return 0; > > } > > dev_base_exit(ioport__remove_arch);