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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4DA1CC4332F for ; Mon, 25 Oct 2021 19:55:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 31A3D60187 for ; Mon, 25 Oct 2021 19:55:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239666AbhJYT5Z (ORCPT ); Mon, 25 Oct 2021 15:57:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:42516 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237510AbhJYTwl (ORCPT ); Mon, 25 Oct 2021 15:52:41 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9F973611C3; Mon, 25 Oct 2021 19:43:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1635191035; bh=XAZI9IdXUAp0hXWlvq+dsmpgWWX95+qTDj/WBP7VN50=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Q74XeOCxLdv7Lr99mhjlpOu2KIrn9vewFlRrJEwojiAdHyhFiSqUh6CW3MBngQSi0 LqC5SUVDlEOrlYUU7VYIewvobEYQCwZmx4ujuX6U5yFk9Od7LGVWgIHfSi6ehV5Afo bjtcwNi1FoaBa6aaEvhPanFw8S44i9ggEzygomEU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Felix Wilhelm , Maxim Levitsky , Paolo Bonzini Subject: [PATCH 5.14 110/169] KVM: SEV-ES: go over the sev_pio_data buffer in multiple passes if needed Date: Mon, 25 Oct 2021 21:14:51 +0200 Message-Id: <20211025191031.990100427@linuxfoundation.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211025191017.756020307@linuxfoundation.org> References: <20211025191017.756020307@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Paolo Bonzini commit 95e16b4792b0429f1933872f743410f00e590c55 upstream. The PIO scratch buffer is larger than a single page, and therefore it is not possible to copy it in a single step to vcpu->arch/pio_data. Bound each call to emulator_pio_in/out to a single page; keep track of how many I/O operations are left in vcpu->arch.sev_pio_count, so that the operation can be restarted in the complete_userspace_io callback. For OUT, this means that the previous kvm_sev_es_outs implementation becomes an iterator of the loop, and we can consume the sev_pio_data buffer before leaving to userspace. For IN, instead, consuming the buffer and decreasing sev_pio_count is always done in the complete_userspace_io callback, because that is when the memcpy is done into sev_pio_data. Cc: stable@vger.kernel.org Fixes: 7ed9abfe8e9f ("KVM: SVM: Support string IO operations for an SEV-ES guest") Reported-by: Felix Wilhelm Reviewed-by: Maxim Levitsky Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/kvm_host.h | 1 arch/x86/kvm/x86.c | 72 +++++++++++++++++++++++++++++++--------- 2 files changed, 57 insertions(+), 16 deletions(-) --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -696,6 +696,7 @@ struct kvm_vcpu_arch { struct kvm_pio_request pio; void *pio_data; void *sev_pio_data; + unsigned sev_pio_count; u8 event_exit_inst_len; --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12321,38 +12321,77 @@ int kvm_sev_es_mmio_read(struct kvm_vcpu EXPORT_SYMBOL_GPL(kvm_sev_es_mmio_read); static int kvm_sev_es_outs(struct kvm_vcpu *vcpu, unsigned int size, - unsigned int port, unsigned int count) + unsigned int port); + +static int complete_sev_es_emulated_outs(struct kvm_vcpu *vcpu) +{ + int size = vcpu->arch.pio.size; + int port = vcpu->arch.pio.port; + + vcpu->arch.pio.count = 0; + if (vcpu->arch.sev_pio_count) + return kvm_sev_es_outs(vcpu, size, port); + return 1; +} + +static int kvm_sev_es_outs(struct kvm_vcpu *vcpu, unsigned int size, + unsigned int port) { - int ret = emulator_pio_out(vcpu, size, port, - vcpu->arch.sev_pio_data, count); + for (;;) { + unsigned int count = + min_t(unsigned int, PAGE_SIZE / size, vcpu->arch.sev_pio_count); + int ret = emulator_pio_out(vcpu, size, port, vcpu->arch.sev_pio_data, count); + + /* memcpy done already by emulator_pio_out. */ + vcpu->arch.sev_pio_count -= count; + vcpu->arch.sev_pio_data += count * vcpu->arch.pio.size; + if (!ret) + break; - if (ret) { /* Emulation done by the kernel. */ - return ret; + if (!vcpu->arch.sev_pio_count) + return 1; } - vcpu->arch.pio.count = 0; + vcpu->arch.complete_userspace_io = complete_sev_es_emulated_outs; return 0; } +static int kvm_sev_es_ins(struct kvm_vcpu *vcpu, unsigned int size, + unsigned int port); + +static void advance_sev_es_emulated_ins(struct kvm_vcpu *vcpu) +{ + unsigned count = vcpu->arch.pio.count; + complete_emulator_pio_in(vcpu, vcpu->arch.sev_pio_data); + vcpu->arch.sev_pio_count -= count; + vcpu->arch.sev_pio_data += count * vcpu->arch.pio.size; +} + static int complete_sev_es_emulated_ins(struct kvm_vcpu *vcpu) { - memcpy(vcpu->arch.sev_pio_data, vcpu->arch.pio_data, - vcpu->arch.pio.count * vcpu->arch.pio.size); - vcpu->arch.pio.count = 0; + int size = vcpu->arch.pio.size; + int port = vcpu->arch.pio.port; + advance_sev_es_emulated_ins(vcpu); + if (vcpu->arch.sev_pio_count) + return kvm_sev_es_ins(vcpu, size, port); return 1; } static int kvm_sev_es_ins(struct kvm_vcpu *vcpu, unsigned int size, - unsigned int port, unsigned int count) + unsigned int port) { - int ret = emulator_pio_in(vcpu, size, port, - vcpu->arch.sev_pio_data, count); + for (;;) { + unsigned int count = + min_t(unsigned int, PAGE_SIZE / size, vcpu->arch.sev_pio_count); + if (!__emulator_pio_in(vcpu, size, port, count)) + break; - if (ret) { /* Emulation done by the kernel. */ - return ret; + advance_sev_es_emulated_ins(vcpu); + if (!vcpu->arch.sev_pio_count) + return 1; } vcpu->arch.complete_userspace_io = complete_sev_es_emulated_ins; @@ -12364,8 +12403,9 @@ int kvm_sev_es_string_io(struct kvm_vcpu int in) { vcpu->arch.sev_pio_data = data; - return in ? kvm_sev_es_ins(vcpu, size, port, count) - : kvm_sev_es_outs(vcpu, size, port, count); + vcpu->arch.sev_pio_count = count; + return in ? kvm_sev_es_ins(vcpu, size, port) + : kvm_sev_es_outs(vcpu, size, port); } EXPORT_SYMBOL_GPL(kvm_sev_es_string_io);