From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9BE5A1B581F for ; Wed, 31 Jul 2024 15:53:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722441194; cv=none; b=juJn3Y2DvrBcDLDZNLuPhMH2tkCLwf7+ucmyTpNLgZ05+exNTQ6g5vP2P1UT3I3SjGRPJIpp6urJI7z6p/v2QIV2Sq92YhkvVp43FmJnU+mW5zJ8x5oKJ3sdaUQFHR5ybDokT5yBovOVHOZgjRUOiuGMAgyFSZrV79s28yVHMPI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722441194; c=relaxed/simple; bh=GiWuXJHUEoAKmVL2TSM7QKFuD/UvLsAiKfix5ofjpGo=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=bqIfCuf0NZlvId9brSpp/M8WqS7Vnrca8Ff3ZkFYNg0QhZGFb/9i70FM2wkjw03unqkLFkPLaOpgn9dCLEgmPujyXnSm1n4ItpppWodoLGWjetD1mmHXTm8ClCtxVUoyjIDj2yR/j1lNDZGp9fEwev4bfF0abfp9JeVloIYSbCc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=NDEL5s+H; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="NDEL5s+H" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 83A6FC4AF09; Wed, 31 Jul 2024 15:53:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722441194; bh=GiWuXJHUEoAKmVL2TSM7QKFuD/UvLsAiKfix5ofjpGo=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=NDEL5s+HOh5f2IKq6KZPwRDZImjyHYYttwer3GYbirMSM8UyZYUbCaOjK8KyoX3Ob ALn83luZ+VtzoQRR0JxZW0gAH6WcSzKNDvW+0wbJSP5iugX6z+w9HreE9xAiogFCEU raoF8d376fVD/pN3/QIvo5FCS0obgTk4aNSI1RFw7CUgFZqrWH0TM8DwkQ6LTfJmaU lsXvf073Z/miZ9s0Z2jw5WOQKqHa/sGPjDu3oC3MRdet0LYNqsADAjpPlYCvCzraWx sjiBK0wUerhD9/6rql80N6W/iaDWYtfRkgzb+vrWkIWhqQrEFhTENkmIe+8Lu3zVTm oNk8fjr3ncGQA== X-Mailer: emacs 31.0.50 (via feedmail 11-beta-1 I) From: Aneesh Kumar K.V To: Will Deacon Cc: linux-arm-kernel@lists.infradead.org, Sudeep Holla , Catalin Marinas , Lorenzo Pieralisi , Suzuki Poulose , Steven Price , Oliver Upton , Marc Zyngier , linux-coco@lists.linux.dev Subject: Re: [PATCH 1/6] firmware/smccc: Call arch-specific hook on discovering KVM services In-Reply-To: <20240731155045.GA3296@willie-the-truck> References: <20240730151113.1497-1-will@kernel.org> <20240730151113.1497-2-will@kernel.org> <20240731155045.GA3296@willie-the-truck> Date: Wed, 31 Jul 2024 21:23:04 +0530 Message-ID: Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Will Deacon writes: > On Wed, Jul 31, 2024 at 08:11:16PM +0530, Aneesh Kumar K.V wrote: >> Will Deacon writes: >> >> > From: Marc Zyngier >> > >> > arm64 will soon require its own callback to initialise services >> > that are only available on this architecture. Introduce a hook >> > that can be overloaded by the architecture. >> > >> > Signed-off-by: Marc Zyngier >> > Signed-off-by: Will Deacon >> > --- >> > arch/arm/include/asm/hypervisor.h | 2 ++ >> > arch/arm64/include/asm/hypervisor.h | 4 ++++ >> > drivers/firmware/smccc/kvm_guest.c | 2 ++ >> > 3 files changed, 8 insertions(+) >> > >> > diff --git a/arch/arm/include/asm/hypervisor.h b/arch/arm/include/asm/hypervisor.h >> > index bd61502b9715..8a648e506540 100644 >> > --- a/arch/arm/include/asm/hypervisor.h >> > +++ b/arch/arm/include/asm/hypervisor.h >> > @@ -7,4 +7,6 @@ >> > void kvm_init_hyp_services(void); >> > bool kvm_arm_hyp_service_available(u32 func_id); >> > >> > +static inline void kvm_arch_init_hyp_services(void) { }; >> > + >> > #endif >> > diff --git a/arch/arm64/include/asm/hypervisor.h b/arch/arm64/include/asm/hypervisor.h >> > index 0ae427f352c8..8cab2ab535b7 100644 >> > --- a/arch/arm64/include/asm/hypervisor.h >> > +++ b/arch/arm64/include/asm/hypervisor.h >> > @@ -7,4 +7,8 @@ >> > void kvm_init_hyp_services(void); >> > bool kvm_arm_hyp_service_available(u32 func_id); >> > >> > +static inline void kvm_arch_init_hyp_services(void) >> > +{ >> > +}; >> > + >> > #endif >> > diff --git a/drivers/firmware/smccc/kvm_guest.c b/drivers/firmware/smccc/kvm_guest.c >> > index 89a68e7eeaa6..f3319be20b36 100644 >> > --- a/drivers/firmware/smccc/kvm_guest.c >> > +++ b/drivers/firmware/smccc/kvm_guest.c >> > @@ -39,6 +39,8 @@ void __init kvm_init_hyp_services(void) >> > >> > pr_info("hypervisor services detected (0x%08lx 0x%08lx 0x%08lx 0x%08lx)\n", >> > res.a3, res.a2, res.a1, res.a0); >> > + >> > + kvm_arch_init_hyp_services(); >> > } >> > >> >> That is a bit late to detect RMM? One of the requirements is to >> figure out the pgprot_t flags for early_ioremap so that "earlycon" will >> work (by mapping the address as shared alias). To do that we need to >> make an RSI call to detect PROT_NS_SHARED mask as below. >> >> if (rsi_get_realm_config(&config)) >> return; >> prot_ns_shared = BIT(config.ipa_bits - 1); > > Why can't the earlycon MMIO address just have that high bit set? > > I think it's horribly fragile to try detecting all of this stuff before > we're allowed to touch the console. We don't even bother with pKVM -- > it's the guest firmware's responsibility to MMIO_GUARD the UART if it > detects a debuggable payload. > To mark something shared, we need to know the mask value which is returned via rsi_get_realm_config() call. -aneesh