![Linus Torvalds](/assets/img/avatar_default.png)
- FIFO event channels. Key advantages: support for over 100,000 events (2^17), 16 different event priorities, improved fairness in event latency through the use of FIFOs. - Xen PVH support. "It’s a fully PV kernel mode, running with paravirtualized disk and network, paravirtualized interrupts and timers, no emulated devices of any kind (and thus no qemu), no BIOS or legacy boot — but instead of requiring PV MMU, it uses the HVM hardware extensions to virtualize the pagetables, as well as system calls and other privileged operations." (from "The Paravirtualization Spectrum, Part 2: From poles to a spectrum") Bug-fixes: - Fixes in balloon driver (refactor and make it work under ARM) - Allow xenfb to be used in HVM guests. - Allow xen_platform_pci=0 to work properly. - Refactors in event channels. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAABAgAGBQJS4BmLAAoJEFjIrFwIi8fJ4SAH/iNGESowgMhfW64vRA8pBWq+ NRJpUjYjjwmbxpwoNl6NPwn15cIXFyc3sMtvvrDD3taRDyko2RFuT+NTjpO05xPh d/cRpRXpXERHoiFgPf/WTp7ONBDhvPtHG0+BzJKwgqEIOUYXdbhD+gEjaVlFJScS CAY68OLmk7XYMSZBNzPfKNbSCyhVgZF7wpaimK9lxZBKsFRCDIq6jIyrAsC8epIL 6V/V4l2S6lk/uUeGB6ULphYeINjI2kkpbSfCd1vyenLfWpVscc2o8uWEYFcZMAxy V4HpsoseuqrfdDqgPfud3VgogdISvbkCvDfW85rzfDP4MWxei2mVHFtJ/gSBV+g= =ToNG -----END PGP SIGNATURE----- Merge tag 'stable/for-linus-3.14-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull Xen updates from Konrad Rzeszutek Wilk: "Two major features that Xen community is excited about: The first is event channel scalability by David Vrabel - we switch over from an two-level per-cpu bitmap of events (IRQs) - to an FIFO queue with priorities. This lets us be able to handle more events, have lower latency, and better scalability. Good stuff. The other is PVH by Mukesh Rathor. In short, PV is a mode where the kernel lets the hypervisor program page-tables, segments, etc. With EPT/NPT capabilities in current processors, the overhead of doing this in an HVM (Hardware Virtual Machine) container is much lower than the hypervisor doing it for us. In short we let a PV guest run without doing page-table, segment, syscall, etc updates through the hypervisor - instead it is all done within the guest container. It is a "hybrid" PV - hence the 'PVH' name - a PV guest within an HVM container. The major benefits are less code to deal with - for example we only use one function from the the pv_mmu_ops (which has 39 function calls); faster performance for syscall (no context switches into the hypervisor); less traps on various operations; etc. It is still being baked - the ABI is not yet set in stone. But it is pretty awesome and we are excited about it. Lastly, there are some changes to ARM code - you should get a simple conflict which has been resolved in #linux-next. In short, this pull has awesome features. Features: - FIFO event channels. Key advantages: support for over 100,000 events (2^17), 16 different event priorities, improved fairness in event latency through the use of FIFOs. - Xen PVH support. "It’s a fully PV kernel mode, running with paravirtualized disk and network, paravirtualized interrupts and timers, no emulated devices of any kind (and thus no qemu), no BIOS or legacy boot — but instead of requiring PV MMU, it uses the HVM hardware extensions to virtualize the pagetables, as well as system calls and other privileged operations." (from "The Paravirtualization Spectrum, Part 2: From poles to a spectrum") Bug-fixes: - Fixes in balloon driver (refactor and make it work under ARM) - Allow xenfb to be used in HVM guests. - Allow xen_platform_pci=0 to work properly. - Refactors in event channels" * tag 'stable/for-linus-3.14-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (52 commits) xen/pvh: Set X86_CR0_WP and others in CR0 (v2) MAINTAINERS: add git repository for Xen xen/pvh: Use 'depend' instead of 'select'. xen: delete new instances of __cpuinit usage xen/fb: allow xenfb initialization for hvm guests xen/evtchn_fifo: fix error return code in evtchn_fifo_setup() xen-platform: fix error return code in platform_pci_init() xen/pvh: remove duplicated include from enlighten.c xen/pvh: Fix compile issues with xen_pvh_domain() xen: Use dev_is_pci() to check whether it is pci device xen/grant-table: Force to use v1 of grants. xen/pvh: Support ParaVirtualized Hardware extensions (v3). xen/pvh: Piggyback on PVHVM XenBus. xen/pvh: Piggyback on PVHVM for grant driver (v4) xen/grant: Implement an grant frame array struct (v3). xen/grant-table: Refactor gnttab_init xen/grants: Remove gnttab_max_grant_frames dependency on gnttab_init. xen/pvh: Piggyback on PVHVM for event channels (v2) xen/pvh: Update E820 to work with PVH (v2) xen/pvh: Secondary VCPU bringup (non-bootup CPUs) ...
398 lines
8.5 KiB
C
398 lines
8.5 KiB
C
/*
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* Implementation of the Xen vTPM device frontend
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*
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* Author: Daniel De Graaf <dgdegra@tycho.nsa.gov>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2,
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* as published by the Free Software Foundation.
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*/
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#include <linux/errno.h>
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#include <linux/err.h>
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#include <linux/interrupt.h>
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#include <xen/xen.h>
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#include <xen/events.h>
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#include <xen/interface/io/tpmif.h>
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#include <xen/grant_table.h>
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#include <xen/xenbus.h>
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#include <xen/page.h>
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#include "tpm.h"
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#include <xen/platform_pci.h>
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struct tpm_private {
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struct tpm_chip *chip;
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struct xenbus_device *dev;
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struct vtpm_shared_page *shr;
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unsigned int evtchn;
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int ring_ref;
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domid_t backend_id;
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};
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enum status_bits {
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VTPM_STATUS_RUNNING = 0x1,
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VTPM_STATUS_IDLE = 0x2,
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VTPM_STATUS_RESULT = 0x4,
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VTPM_STATUS_CANCELED = 0x8,
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};
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static u8 vtpm_status(struct tpm_chip *chip)
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{
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struct tpm_private *priv = TPM_VPRIV(chip);
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switch (priv->shr->state) {
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case VTPM_STATE_IDLE:
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return VTPM_STATUS_IDLE | VTPM_STATUS_CANCELED;
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case VTPM_STATE_FINISH:
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return VTPM_STATUS_IDLE | VTPM_STATUS_RESULT;
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case VTPM_STATE_SUBMIT:
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case VTPM_STATE_CANCEL: /* cancel requested, not yet canceled */
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return VTPM_STATUS_RUNNING;
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default:
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return 0;
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}
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}
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static bool vtpm_req_canceled(struct tpm_chip *chip, u8 status)
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{
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return status & VTPM_STATUS_CANCELED;
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}
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static void vtpm_cancel(struct tpm_chip *chip)
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{
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struct tpm_private *priv = TPM_VPRIV(chip);
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priv->shr->state = VTPM_STATE_CANCEL;
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wmb();
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notify_remote_via_evtchn(priv->evtchn);
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}
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static unsigned int shr_data_offset(struct vtpm_shared_page *shr)
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{
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return sizeof(*shr) + sizeof(u32) * shr->nr_extra_pages;
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}
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static int vtpm_send(struct tpm_chip *chip, u8 *buf, size_t count)
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{
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struct tpm_private *priv = TPM_VPRIV(chip);
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struct vtpm_shared_page *shr = priv->shr;
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unsigned int offset = shr_data_offset(shr);
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u32 ordinal;
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unsigned long duration;
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if (offset > PAGE_SIZE)
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return -EINVAL;
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if (offset + count > PAGE_SIZE)
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return -EINVAL;
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/* Wait for completion of any existing command or cancellation */
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if (wait_for_tpm_stat(chip, VTPM_STATUS_IDLE, chip->vendor.timeout_c,
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&chip->vendor.read_queue, true) < 0) {
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vtpm_cancel(chip);
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return -ETIME;
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}
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memcpy(offset + (u8 *)shr, buf, count);
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shr->length = count;
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barrier();
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shr->state = VTPM_STATE_SUBMIT;
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wmb();
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notify_remote_via_evtchn(priv->evtchn);
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ordinal = be32_to_cpu(((struct tpm_input_header*)buf)->ordinal);
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duration = tpm_calc_ordinal_duration(chip, ordinal);
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if (wait_for_tpm_stat(chip, VTPM_STATUS_IDLE, duration,
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&chip->vendor.read_queue, true) < 0) {
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/* got a signal or timeout, try to cancel */
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vtpm_cancel(chip);
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return -ETIME;
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}
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return count;
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}
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static int vtpm_recv(struct tpm_chip *chip, u8 *buf, size_t count)
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{
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struct tpm_private *priv = TPM_VPRIV(chip);
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struct vtpm_shared_page *shr = priv->shr;
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unsigned int offset = shr_data_offset(shr);
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size_t length = shr->length;
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if (shr->state == VTPM_STATE_IDLE)
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return -ECANCELED;
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/* In theory the wait at the end of _send makes this one unnecessary */
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if (wait_for_tpm_stat(chip, VTPM_STATUS_RESULT, chip->vendor.timeout_c,
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&chip->vendor.read_queue, true) < 0) {
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vtpm_cancel(chip);
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return -ETIME;
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}
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if (offset > PAGE_SIZE)
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return -EIO;
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if (offset + length > PAGE_SIZE)
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length = PAGE_SIZE - offset;
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if (length > count)
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length = count;
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memcpy(buf, offset + (u8 *)shr, length);
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return length;
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}
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static const struct tpm_class_ops tpm_vtpm = {
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.status = vtpm_status,
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.recv = vtpm_recv,
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.send = vtpm_send,
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.cancel = vtpm_cancel,
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.req_complete_mask = VTPM_STATUS_IDLE | VTPM_STATUS_RESULT,
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.req_complete_val = VTPM_STATUS_IDLE | VTPM_STATUS_RESULT,
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.req_canceled = vtpm_req_canceled,
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};
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static irqreturn_t tpmif_interrupt(int dummy, void *dev_id)
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{
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struct tpm_private *priv = dev_id;
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switch (priv->shr->state) {
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case VTPM_STATE_IDLE:
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case VTPM_STATE_FINISH:
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wake_up_interruptible(&priv->chip->vendor.read_queue);
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break;
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case VTPM_STATE_SUBMIT:
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case VTPM_STATE_CANCEL:
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default:
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break;
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}
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return IRQ_HANDLED;
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}
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static int setup_chip(struct device *dev, struct tpm_private *priv)
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{
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struct tpm_chip *chip;
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chip = tpm_register_hardware(dev, &tpm_vtpm);
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if (!chip)
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return -ENODEV;
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init_waitqueue_head(&chip->vendor.read_queue);
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priv->chip = chip;
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TPM_VPRIV(chip) = priv;
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return 0;
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}
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/* caller must clean up in case of errors */
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static int setup_ring(struct xenbus_device *dev, struct tpm_private *priv)
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{
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struct xenbus_transaction xbt;
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const char *message = NULL;
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int rv;
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priv->shr = (void *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
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if (!priv->shr) {
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xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
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return -ENOMEM;
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}
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rv = xenbus_grant_ring(dev, virt_to_mfn(priv->shr));
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if (rv < 0)
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return rv;
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priv->ring_ref = rv;
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rv = xenbus_alloc_evtchn(dev, &priv->evtchn);
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if (rv)
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return rv;
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rv = bind_evtchn_to_irqhandler(priv->evtchn, tpmif_interrupt, 0,
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"tpmif", priv);
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if (rv <= 0) {
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xenbus_dev_fatal(dev, rv, "allocating TPM irq");
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return rv;
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}
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priv->chip->vendor.irq = rv;
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again:
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rv = xenbus_transaction_start(&xbt);
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if (rv) {
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xenbus_dev_fatal(dev, rv, "starting transaction");
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return rv;
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}
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rv = xenbus_printf(xbt, dev->nodename,
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"ring-ref", "%u", priv->ring_ref);
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if (rv) {
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message = "writing ring-ref";
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goto abort_transaction;
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}
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rv = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
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priv->evtchn);
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if (rv) {
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message = "writing event-channel";
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goto abort_transaction;
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}
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rv = xenbus_printf(xbt, dev->nodename, "feature-protocol-v2", "1");
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if (rv) {
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message = "writing feature-protocol-v2";
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goto abort_transaction;
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}
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rv = xenbus_transaction_end(xbt, 0);
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if (rv == -EAGAIN)
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goto again;
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if (rv) {
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xenbus_dev_fatal(dev, rv, "completing transaction");
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return rv;
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}
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xenbus_switch_state(dev, XenbusStateInitialised);
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return 0;
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abort_transaction:
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xenbus_transaction_end(xbt, 1);
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if (message)
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xenbus_dev_error(dev, rv, "%s", message);
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return rv;
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}
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static void ring_free(struct tpm_private *priv)
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{
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if (!priv)
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return;
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if (priv->ring_ref)
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gnttab_end_foreign_access(priv->ring_ref, 0,
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(unsigned long)priv->shr);
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else
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free_page((unsigned long)priv->shr);
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if (priv->chip && priv->chip->vendor.irq)
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unbind_from_irqhandler(priv->chip->vendor.irq, priv);
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kfree(priv);
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}
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static int tpmfront_probe(struct xenbus_device *dev,
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const struct xenbus_device_id *id)
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{
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struct tpm_private *priv;
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int rv;
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priv = kzalloc(sizeof(*priv), GFP_KERNEL);
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if (!priv) {
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xenbus_dev_fatal(dev, -ENOMEM, "allocating priv structure");
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return -ENOMEM;
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}
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rv = setup_chip(&dev->dev, priv);
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if (rv) {
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kfree(priv);
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return rv;
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}
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rv = setup_ring(dev, priv);
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if (rv) {
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tpm_remove_hardware(&dev->dev);
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ring_free(priv);
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return rv;
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}
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tpm_get_timeouts(priv->chip);
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return rv;
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}
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static int tpmfront_remove(struct xenbus_device *dev)
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{
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struct tpm_chip *chip = dev_get_drvdata(&dev->dev);
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struct tpm_private *priv = TPM_VPRIV(chip);
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tpm_remove_hardware(&dev->dev);
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ring_free(priv);
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TPM_VPRIV(chip) = NULL;
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return 0;
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}
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static int tpmfront_resume(struct xenbus_device *dev)
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{
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/* A suspend/resume/migrate will interrupt a vTPM anyway */
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tpmfront_remove(dev);
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return tpmfront_probe(dev, NULL);
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}
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static void backend_changed(struct xenbus_device *dev,
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enum xenbus_state backend_state)
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{
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int val;
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switch (backend_state) {
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case XenbusStateInitialised:
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case XenbusStateConnected:
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if (dev->state == XenbusStateConnected)
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break;
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if (xenbus_scanf(XBT_NIL, dev->otherend,
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"feature-protocol-v2", "%d", &val) < 0)
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val = 0;
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if (!val) {
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xenbus_dev_fatal(dev, -EINVAL,
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"vTPM protocol 2 required");
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return;
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}
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xenbus_switch_state(dev, XenbusStateConnected);
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break;
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case XenbusStateClosing:
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case XenbusStateClosed:
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device_unregister(&dev->dev);
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xenbus_frontend_closed(dev);
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break;
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default:
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break;
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}
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}
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static const struct xenbus_device_id tpmfront_ids[] = {
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{ "vtpm" },
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{ "" }
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};
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MODULE_ALIAS("xen:vtpm");
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static DEFINE_XENBUS_DRIVER(tpmfront, ,
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.probe = tpmfront_probe,
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.remove = tpmfront_remove,
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.resume = tpmfront_resume,
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.otherend_changed = backend_changed,
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);
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static int __init xen_tpmfront_init(void)
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{
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if (!xen_domain())
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return -ENODEV;
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if (!xen_has_pv_devices())
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return -ENODEV;
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return xenbus_register_frontend(&tpmfront_driver);
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}
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module_init(xen_tpmfront_init);
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static void __exit xen_tpmfront_exit(void)
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{
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xenbus_unregister_driver(&tpmfront_driver);
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}
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module_exit(xen_tpmfront_exit);
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MODULE_AUTHOR("Daniel De Graaf <dgdegra@tycho.nsa.gov>");
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MODULE_DESCRIPTION("Xen vTPM Driver");
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MODULE_LICENSE("GPL");
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