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Mon, 30 Nov 2020 10:32:19 +0000 (UTC) Received: by mail-lj1-x244.google.com with SMTP id y7so17019212lji.8 for ; Mon, 30 Nov 2020 02:32:19 -0800 (PST) Received: from otyshchenko.www.tendawifi.com ([212.22.223.21]) by smtp.gmail.com with ESMTPSA id 136sm2399393lfb.62.2020.11.30.02.32.17 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 30 Nov 2020 02:32:17 -0800 (PST) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: bd410a64-db72-4953-8a83-8438d237a04e DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=cBlwWPGKzEGxAAOiUlGssFOYms5RMEboYfXpdUQmleg=; b=jbVzVpyjkJDq4y8E5MaaQa+5tPgBBO1gUbVpVCKJCv2sSzYgKO3ASyhFoToueFJoVc BoO3t1tOtefZJ73282cqMkDoH4NzpFkoW4BF9j3/gvePFx9jgK0U1prSV/lnT4Jwq8Ho +oBmxy1QcC3yQeMiMPN10o6IzCl0t/8uSMx5vTHvTULDPGoDlEHNshDRMCBrF+uMRdo8 3nCzit3goLRD5gtD1U7Pv4Z51Nw2W0O1ndKS6o4LLAYQrpIV0CDwyREPilAGWAeDhTrB a0o3nXnjWT8KFbvvVxjxMn0y/yG6WYMMc8fMO7B5p5J30+u+kSJT8Mn0VflJVHbbTGbb ug2w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=cBlwWPGKzEGxAAOiUlGssFOYms5RMEboYfXpdUQmleg=; b=dYPVcQiMvjEoxhuO45gToD4fFUGiev9pPeW4zph3SMVbA5Ud4Gui/+TGAenE9q0aYq +NyYQ35G4W9G09QWKN86EPkwKueqoUNbEqvOqIXxgByzaK5iw7XOeRf/roZjraShe8or ksXdR2M4EXyhU+TB5QvgjuE3A0soPpwgWNbraEI5CsIrSN2hogOZHwWjdpG+Nu9hkYcf 4nTPnNrUnGM0CjYWwxWamgwav0Ll4HehGulrw1ywLzZ1w218Nt6RxFmzICenTVDPrHrY GufP4dC5JQF3/JmdH4uok+ZONktvFjNtCTef0PBRJwhqfdUCHBIhvfvklgrWFI8GtgCg 1seQ== X-Gm-Message-State: AOAM531o6quIwMq4xf6uW17YM2TaA9oA8Qd0/FuBpEANotZlxvFa6NCS 6CmE6ih1oaDefD2ARLKLVSbulJdOQmhNsA== X-Google-Smtp-Source: ABdhPJzYADassTkhsXa92/kInhE69nL47Ls14oh6muNSJGEg1ZrkemxdIuJKh8G5Qfuaxk8MNo3ECg== X-Received: by 2002:a2e:5c2:: with SMTP id 185mr9454661ljf.79.1606732338314; Mon, 30 Nov 2020 02:32:18 -0800 (PST) From: Oleksandr Tyshchenko To: xen-devel@lists.xenproject.org Cc: Oleksandr Tyshchenko , Stefano Stabellini , Julien Grall , Volodymyr Babchuk , Julien Grall Subject: [PATCH V3 19/23] xen/arm: io: Abstract sign-extension Date: Mon, 30 Nov 2020 12:31:34 +0200 Message-Id: <1606732298-22107-20-git-send-email-olekstysh@gmail.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1606732298-22107-1-git-send-email-olekstysh@gmail.com> References: <1606732298-22107-1-git-send-email-olekstysh@gmail.com> From: Oleksandr Tyshchenko In order to avoid code duplication (both handle_read() and handle_ioserv() contain the same code for the sign-extension) put this code to a common helper to be used for both. Signed-off-by: Oleksandr Tyshchenko CC: Julien Grall --- Please note, this is a split/cleanup/hardening of Julien's PoC: "Add support for Guest IO forwarding to a device emulator" Changes V1 -> V2: - new patch Changes V2 -> V3: - no changes --- --- xen/arch/arm/io.c | 18 ++---------------- xen/arch/arm/ioreq.c | 17 +---------------- xen/include/asm-arm/traps.h | 24 ++++++++++++++++++++++++ 3 files changed, 27 insertions(+), 32 deletions(-) diff --git a/xen/arch/arm/io.c b/xen/arch/arm/io.c index f44cfd4..8d6ec6c 100644 --- a/xen/arch/arm/io.c +++ b/xen/arch/arm/io.c @@ -23,6 +23,7 @@ #include #include #include +#include #include #include "decode.h" @@ -39,26 +40,11 @@ static enum io_state handle_read(const struct mmio_handler *handler, * setting r). */ register_t r = 0; - uint8_t size = (1 << dabt.size) * 8; if ( !handler->ops->read(v, info, &r, handler->priv) ) return IO_ABORT; - /* - * Sign extend if required. - * Note that we expect the read handler to have zeroed the bits - * outside the requested access size. - */ - if ( dabt.sign && (r & (1UL << (size - 1))) ) - { - /* - * We are relying on register_t using the same as - * an unsigned long in order to keep the 32-bit assembly - * code smaller. - */ - BUILD_BUG_ON(sizeof(register_t) != sizeof(unsigned long)); - r |= (~0UL) << size; - } + r = sign_extend(dabt, r); set_user_reg(regs, dabt.reg, r); diff --git a/xen/arch/arm/ioreq.c b/xen/arch/arm/ioreq.c index f08190c..2f39289 100644 --- a/xen/arch/arm/ioreq.c +++ b/xen/arch/arm/ioreq.c @@ -28,7 +28,6 @@ enum io_state handle_ioserv(struct cpu_user_regs *regs, struct vcpu *v) const union hsr hsr = { .bits = regs->hsr }; const struct hsr_dabt dabt = hsr.dabt; /* Code is similar to handle_read */ - uint8_t size = (1 << dabt.size) * 8; register_t r = v->io.req.data; /* We are done with the IO */ @@ -37,21 +36,7 @@ enum io_state handle_ioserv(struct cpu_user_regs *regs, struct vcpu *v) if ( dabt.write ) return IO_HANDLED; - /* - * Sign extend if required. - * Note that we expect the read handler to have zeroed the bits - * outside the requested access size. - */ - if ( dabt.sign && (r & (1UL << (size - 1))) ) - { - /* - * We are relying on register_t using the same as - * an unsigned long in order to keep the 32-bit assembly - * code smaller. - */ - BUILD_BUG_ON(sizeof(register_t) != sizeof(unsigned long)); - r |= (~0UL) << size; - } + r = sign_extend(dabt, r); set_user_reg(regs, dabt.reg, r); diff --git a/xen/include/asm-arm/traps.h b/xen/include/asm-arm/traps.h index 997c378..e301c44 100644 --- a/xen/include/asm-arm/traps.h +++ b/xen/include/asm-arm/traps.h @@ -83,6 +83,30 @@ static inline bool VABORT_GEN_BY_GUEST(const struct cpu_user_regs *regs) (unsigned long)abort_guest_exit_end == regs->pc; } +/* Check whether the sign extension is required and perform it */ +static inline register_t sign_extend(const struct hsr_dabt dabt, register_t r) +{ + uint8_t size = (1 << dabt.size) * 8; + + /* + * Sign extend if required. + * Note that we expect the read handler to have zeroed the bits + * outside the requested access size. + */ + if ( dabt.sign && (r & (1UL << (size - 1))) ) + { + /* + * We are relying on register_t using the same as + * an unsigned long in order to keep the 32-bit assembly + * code smaller. + */ + BUILD_BUG_ON(sizeof(register_t) != sizeof(unsigned long)); + r |= (~0UL) << size; + } + + return r; +} + #endif /* __ASM_ARM_TRAPS__ */ /* * Local variables: -- 2.7.4