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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [RFC] WIP: optee: add OP-TEE mediator
Hi Stefano,
On Fri, Dec 01, 2017 at 02:58:57PM -0800, Stefano Stabellini wrote:
> On Mon, 27 Nov 2017, Volodymyr Babchuk wrote:
> > This is follow-up to our conversation during community call.
> > You asked me to send OP-TEE mediator as a patch, so we can
> > discuss it in the mailing list. So, there it is. I squashed
> > two patches into one and skipped patches that we already
> > discussed.
> >
> > So, this is basically all what is needed to support OP-TEE in XEN.
> > There are some TODOs left all over the code. But, I don't
> > expect that TODOs implementation would significantly
> > increase codebase. Currently mediator parses requests to perform
> > addresses translation and that's all what is should be done
> > to allow guests to work with OP-TEE.
> >
> > This become possible because I completely revisited virtualization
> > support in OP-TEE. I have found way to enforce complete isolation
> > between different guest states. This lifts many questions like usage
> > quotas, RPC routing, sudden guest death, data isolation, etc.
> >
> > I'm aware that I didn't addressed all comments from previous
> > discussion. Sorry for this. I'm currently busy with OP-TEE,
> > and I think proper mediator implementation will be possible
> > only after I'll stabilize OP-TEE part.
> >
> > So I don't ask anybody to do thorough review. I just want to
> > share my status and discuss this code a whole.
>
> Thank you for sharing! Actually, I think it is not too bad as a starting
> point.
>
> I'll also try to summarize some key concept we have been discussing
> about OP-TEE support in Xen.
>
>
> = Xen cannot protect the system from a broken/insecure OP-TEE =
>
> OP-TEE runs at a higher privilege level than Xen, thus, we can't really
> expect Xen to protect the system from a broken OP-TEE. Also, Xen cannot
> really protect OP-TEE from a malicious caller.
Yes, this is right.
> What we can and should do is to protect Xen, the OP-TEE mediator in Xen
> specifically, from malicious attackers.
>
> In other words, we are not responsible if a call, forwarded to OP-TEE by
> Xen, ends up crashing OP-TEE, therefore taking down the system.
>
> However, we have to pay special care to avoid callers to crash or take
> over the mediator in Xen. We also have to pay attention so that a caller
> won't be able to exhaust Xen resources or DOS Xen (allocate too much
> memory, infinite loops in Xen, etc). This brings me to the next topic.
Yes, I see where are you going.
>
> = Error checking / DOS protection =
>
> We need powerful checks on arguments passed by the caller and evaluated
> by the mediator.
>
> For example, we cannot expect the guest to actually pass arguments in
> the format expected by translate_params. ctx->xen_arg could be
> gibberish.
Yes. The same arguments stands also for OP-TEE itself. OP-TEE checks
validity of arguments and mediator should do the same. Actaully, I
implemented this checks in mediator.
> From the resource allocation point of view, it looks like every
> handle_std_call allocates a new context; every copy_std_request
> allocates a new Xen page. It would be easy to exhaust Xen resources.
> Maybe we need a max concurrent request limit or max page allocation per
> domain or something of the kind.
This is a very good point. Thanks. Yes, it is currently missing.
Is there any mechanism in XEN to provide quotas? I think, this mediator
is not the single entity that allocates memory to handle guest calls?
Also, this problem is somewhat handled from OP-TEE site: it have limited
number of threads, so it can't handle many STD call simultaneously. But
I wouldn't rely on OP-TEE there, of course.
>
>
> = Locks and Lists =
>
> The current lock and list is global. Do you think it should actually be
> global or per-domain? I do realize that only dom0 is allowed to make
> calls now so the question for the moment is not too useful.
Agree lists (and corresponding locks) should be domain-bound. This is
in my todo list, which is included in this patch.
>
> = Xen command forwarding =
>
> In the code below, it looks like Xen is forwarding everything to OP-TEE.
> Are there some commands Xen should avoid forwarding? Should we have a
> whitelist or a blacklist?
My code implements whitelists (at least, I hope so :-) ). It forwards
only known requests. If it does not know type of the request, it
returns error back to a caller.
>
> = Long running OP-TEE commands and interruptions =
>
> I have been told that some OP-TEE RPC commands might take long to
> complete. Is that right? Like for example one of the
> OPTEE_MSG_RPC_CMD_*?
>
> If so, we need to think what to do in those cases. Specifically, do we
> need a technique to restart certain commands in Xen, so that when they
> run for too long and get interrupted by something (such as an
> interrupt) we know how to restart them? In fact, do we need to setup a
> timer interrupt to make sure the command doesn't block Xen for too long,
> consuming the next vcpu's slot as well?
You will rely on OP-TEE there. Mediator (and, thus, XEN) does nothing
heavy, it just forwards call to OP-TEE. OP-TEE in turn does RPC return
to handle any IRQ that comes to the system. In this way, XEN gets
control back and returns control back to guest. This is perfect time
for XEN (and for guest) to handle interrupts, switchs running
guests/tasks, etc.
>
> = Page pinning =
>
> Guest pages passed to OP-TEE need to be pinned (otherwise Xen doesn't
> guarantee they'll be available). I think the right function to call for
> that is get_page_from_gfn or get_page.
Yes, I need to pin pages. I have this in my TODO list. Question is how
to do this in a proper way. Julien has objections against get_page()
as I can see.
>
>
> > ---
> >
> > Add OP-TEE mediator as an example how TEE mediator framework
> > works.
> >
> > OP-TEE mediator support address translation for DomUs.
> > It tracks execution of STD calls, correctly handles memory-related RPC
> > requests, tracks buffer allocated for RPCs.
> >
> > With this patch OP-TEE successfully passes own tests, while client is
> > running in DomU. Currently it lacks some code for exceptional cases,
> > because this patch was used mostly to debug virtualization in OP-TEE.
> > Nevertheless, it provides all features needed for OP-TEE mediation.
> >
> > WARNING: This is a development patch, it does not cover all corner
> > cases, so, please don't use it in production.
> >
> > It was tested on RCAR Salvator-M3 board.
> >
> > Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>
> > ---
> > xen/arch/arm/tee/Kconfig | 4 +
> > xen/arch/arm/tee/Makefile | 1 +
> > xen/arch/arm/tee/optee.c | 765
> > +++++++++++++++++++++++++++++++++++++++++++
> > xen/arch/arm/tee/optee_smc.h | 50 +++
> > 4 files changed, 820 insertions(+)
> > create mode 100644 xen/arch/arm/tee/optee.c
> >
> > diff --git a/xen/arch/arm/tee/Kconfig b/xen/arch/arm/tee/Kconfig
> > index e69de29..7c6b5c6 100644
> > --- a/xen/arch/arm/tee/Kconfig
> > +++ b/xen/arch/arm/tee/Kconfig
> > @@ -0,0 +1,4 @@
> > +config ARM_OPTEE
> > + bool "Enable OP-TEE mediator"
> > + default n
> > + depends on ARM_TEE
> > diff --git a/xen/arch/arm/tee/Makefile b/xen/arch/arm/tee/Makefile
> > index c54d479..9d93b42 100644
> > --- a/xen/arch/arm/tee/Makefile
> > +++ b/xen/arch/arm/tee/Makefile
> > @@ -1 +1,2 @@
> > obj-y += tee.o
> > +obj-$(CONFIG_ARM_OPTEE) += optee.o
> > diff --git a/xen/arch/arm/tee/optee.c b/xen/arch/arm/tee/optee.c
> > new file mode 100644
> > index 0000000..59c3600
> > --- /dev/null
> > +++ b/xen/arch/arm/tee/optee.c
> > @@ -0,0 +1,765 @@
> > +/*
> > + * xen/arch/arm/tee/optee.c
> > + *
> > + * OP-TEE mediator
> > + *
> > + * Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>
> > + * Copyright (c) 2017 EPAM Systems.
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> > + * GNU General Public License for more details.
> > + */
> > +
> > +#include <xen/domain_page.h>
> > +#include <xen/types.h>
> > +#include <xen/sched.h>
> > +
> > +#include <asm/p2m.h>
> > +#include <asm/tee.h>
> > +
> > +#include "optee_msg.h"
> > +#include "optee_smc.h"
> > +
> > +/*
> > + * Global TODO:
> > + * 1. Create per-domain context, where call and shm will be stored
> > + * 2. Pin pages shared between OP-TEE and guest
> > + */
> > +/*
> > + * OP-TEE violates SMCCC when it defines own UID. So we need
> > + * to place bytes in correct order.
> > + */
> > +#define OPTEE_UID (xen_uuid_t){{
> > \
> > + (uint8_t)(OPTEE_MSG_UID_0 >> 0), (uint8_t)(OPTEE_MSG_UID_0 >> 8),
> > \
> > + (uint8_t)(OPTEE_MSG_UID_0 >> 16), (uint8_t)(OPTEE_MSG_UID_0 >> 24),
> > \
> > + (uint8_t)(OPTEE_MSG_UID_1 >> 0), (uint8_t)(OPTEE_MSG_UID_1 >> 8),
> > \
> > + (uint8_t)(OPTEE_MSG_UID_1 >> 16), (uint8_t)(OPTEE_MSG_UID_1 >> 24),
> > \
> > + (uint8_t)(OPTEE_MSG_UID_2 >> 0), (uint8_t)(OPTEE_MSG_UID_2 >> 8),
> > \
> > + (uint8_t)(OPTEE_MSG_UID_2 >> 16), (uint8_t)(OPTEE_MSG_UID_2 >> 24),
> > \
> > + (uint8_t)(OPTEE_MSG_UID_3 >> 0), (uint8_t)(OPTEE_MSG_UID_3 >> 8),
> > \
> > + (uint8_t)(OPTEE_MSG_UID_3 >> 16), (uint8_t)(OPTEE_MSG_UID_3 >> 24),
> > \
> > + }}
> > +
> > +#define MAX_NONCONTIG_ENTRIES 8
> > +
> > +/*
> > + * Call context. OP-TEE can issue mulitple RPC returns during one call.
> > + * We need to preserve context during them.
> > + */
> > +struct std_call_ctx {
> > + struct list_head list;
> > + struct optee_msg_arg *guest_arg;
> > + struct optee_msg_arg *xen_arg;
> > + void *non_contig[MAX_NONCONTIG_ENTRIES];
> > + int non_contig_order[MAX_NONCONTIG_ENTRIES];
> > + int optee_thread_id;
> > + int rpc_op;
> > + domid_t domid;
> > +};
> > +static LIST_HEAD(call_ctx_list);
> > +static DEFINE_SPINLOCK(call_ctx_list_lock);
> > +
> > +/*
> > + * Command buffer shared between OP-TEE and guest.
> > + * Warning! In the proper implementation this SHM buffer *probably* should
> > + * by shadowed by XEN.
> > + * TODO: Reconsider this.
> > + */
> > +struct shm {
> > + struct list_head list;
> > + struct optee_msg_arg *guest_arg;
> > + struct page *guest_page;
> > + mfn_t guest_mfn;
> > + uint64_t cookie;
> > + domid_t domid;
> > +};
> > +
> > +static LIST_HEAD(shm_list);
> > +static DEFINE_SPINLOCK(shm_list_lock);
> > +
> > +static int optee_init(void)
> > +{
> > + printk("OP-TEE mediator init done\n");
> > + return 0;
> > +}
> > +
> > +static void optee_domain_create(struct domain *d)
> > +{
> > + register_t resp[4];
> > + call_smccc_smc(OPTEE_SMC_VM_CREATED,
> > + d->domain_id + 1, 0, 0, 0, 0, 0, 0, resp);
> > + if ( resp[0] != OPTEE_SMC_RETURN_OK )
> > + gprintk(XENLOG_WARNING, "OP-TEE don't want to support domain:
> > %d\n",
> > + (uint32_t)resp[0]);
> > + /* TODO: Change function declaration to be able to retun error */
> > +}
> > +
> > +static void optee_domain_destroy(struct domain *d)
> > +{
> > + register_t resp[4];
> > + call_smccc_smc(OPTEE_SMC_VM_DESTROYED,
> > + d->domain_id + 1, 0, 0, 0, 0, 0, 0, resp);
> > + /* TODO: Clean call contexts and SHMs associated with domain */
> > +}
> > +
> > +static bool forward_call(struct cpu_user_regs *regs)
> > +{
> > + register_t resp[4];
> > +
> > + /* TODO: Use separate registers set to prevent leakage to guest */
> > + call_smccc_smc(get_user_reg(regs, 0),
> > + get_user_reg(regs, 1),
> > + get_user_reg(regs, 2),
> > + get_user_reg(regs, 3),
> > + get_user_reg(regs, 4),
> > + get_user_reg(regs, 5),
> > + get_user_reg(regs, 6),
> > + /* VM id 0 is reserved for hypervisor itself */
> > + current->domain->domain_id + 1,
>
> This doesn't look like it would wrap around safely.
>
>
> > + resp);
> > +
> > + set_user_reg(regs, 0, resp[0]);
> > + set_user_reg(regs, 1, resp[1]);
> > + set_user_reg(regs, 2, resp[2]);
> > + set_user_reg(regs, 3, resp[3]);
> > +
> > + return true;
> > +}
> > +
> > +static struct std_call_ctx *allocate_std_call_ctx(void)
> > +{
> > + struct std_call_ctx *ret;
> > +
> > + ret = xzalloc(struct std_call_ctx);
> > + if ( !ret )
> > + return NULL;
> > +
> > + ret->optee_thread_id = -1;
> > + ret->domid = -1;
> > +
> > + spin_lock(&call_ctx_list_lock);
> > + list_add_tail(&ret->list, &call_ctx_list);
> > + spin_unlock(&call_ctx_list_lock);
> > +
> > + return ret;
> > +}
> > +
> > +static void free_std_call_ctx(struct std_call_ctx *ctx)
> > +{
> > + spin_lock(&call_ctx_list_lock);
> > + list_del(&ctx->list);
> > + spin_unlock(&call_ctx_list_lock);
> > +
> > + if (ctx->xen_arg)
> > + free_xenheap_page(ctx->xen_arg);
> > +
> > + if (ctx->guest_arg)
> > + unmap_domain_page(ctx->guest_arg);
> > +
> > + for (int i = 0; i < MAX_NONCONTIG_ENTRIES; i++) {
> > + if (ctx->non_contig[i])
> > + free_xenheap_pages(ctx->non_contig[i],
> > ctx->non_contig_order[i]);
> > + }
> > +
> > + xfree(ctx);
> > +}
> > +
> > +static struct std_call_ctx *find_ctx(int thread_id, domid_t domid)
> > +{
> > + struct std_call_ctx *ctx;
> > +
> > + spin_lock(&call_ctx_list_lock);
> > + list_for_each_entry( ctx, &call_ctx_list, list )
> > + {
> > + if (ctx->domid == domid && ctx->optee_thread_id == thread_id )
> > + {
> > + spin_unlock(&call_ctx_list_lock);
> > + return ctx;
> > + }
> > + }
> > + spin_unlock(&call_ctx_list_lock);
> > +
> > + return NULL;
> > +}
> > +
> > +#define PAGELIST_ENTRIES_PER_PAGE \
> > + ((OPTEE_MSG_NONCONTIG_PAGE_SIZE / sizeof(u64)) - 1)
> > +
> > +static size_t get_pages_list_size(size_t num_entries)
> > +{
> > + int pages = DIV_ROUND_UP(num_entries, PAGELIST_ENTRIES_PER_PAGE);
> > +
> > + return pages * OPTEE_MSG_NONCONTIG_PAGE_SIZE;
> > +}
> > +
> > +static mfn_t lookup_guest_ram_addr(paddr_t gaddr)
> > +{
> > + mfn_t mfn;
> > + gfn_t gfn;
> > + p2m_type_t t;
> > + gfn = gaddr_to_gfn(gaddr);
> > + mfn = p2m_lookup(current->domain, gfn, &t);
> > + if ( t != p2m_ram_rw || mfn_eq(mfn, INVALID_MFN) ) {
> > + gprintk(XENLOG_INFO, "Domain tries to use invalid gfn\n");
> > + return INVALID_MFN;
> > + }
> > + return mfn;
> > +}
> > +
> > +static struct shm *allocate_and_map_shm(paddr_t gaddr, uint64_t cookie)
> > +{
> > + struct shm *ret;
> > +
> > + ret = xzalloc(struct shm);
> > + if ( !ret )
> > + return NULL;
> > +
> > + ret->guest_mfn = lookup_guest_ram_addr(gaddr);
> > +
> > + if ( mfn_eq(ret->guest_mfn, INVALID_MFN) )
> > + {
> > + xfree(ret);
> > + return NULL;
> > + }
> > +
> > + ret->guest_arg = map_domain_page(ret->guest_mfn);
> > + if ( !ret->guest_arg )
> > + {
> > + gprintk(XENLOG_INFO, "Could not map domain page\n");
> > + xfree(ret);
> > + return NULL;
> > + }
> > + ret->cookie = cookie;
> > + ret->domid = current->domain->domain_id;
> > +
> > + spin_lock(&shm_list_lock);
> > + list_add_tail(&ret->list, &shm_list);
> > + spin_unlock(&shm_list_lock);
> > + return ret;
> > +}
> > +
> > +static void free_shm(uint64_t cookie, domid_t domid)
> > +{
> > + struct shm *shm, *found = NULL;
> > + spin_lock(&shm_list_lock);
> > +
> > + list_for_each_entry( shm, &shm_list, list )
> > + {
> > + if (shm->domid == domid && shm->cookie == cookie )
> > + {
> > + found = shm;
> > + list_del(&found->list);
> > + break;
> > + }
> > + }
> > + spin_unlock(&shm_list_lock);
> > +
> > + if ( !found ) {
> > + return;
> > + }
> > +
> > + if ( found->guest_arg )
> > + unmap_domain_page(found->guest_arg);
> > +
> > + xfree(found);
> > +}
> > +
> > +static struct shm *find_shm(uint64_t cookie, domid_t domid)
> > +{
> > + struct shm *shm;
> > +
> > + spin_lock(&shm_list_lock);
> > + list_for_each_entry( shm, &shm_list, list )
> > + {
> > + if ( shm->domid == domid && shm->cookie == cookie )
> > + {
> > + spin_unlock(&shm_list_lock);
> > + return shm;
> > + }
> > + }
> > + spin_unlock(&shm_list_lock);
> > +
> > + return NULL;
> > +}
> > +
> > +static bool translate_noncontig(struct std_call_ctx *ctx,
> > + struct optee_msg_param *param,
> > + int idx)
> > +{
> > + /*
> > + * Refer to OPTEE_MSG_ATTR_NONCONTIG description in optee_msg.h for
> > details.
> > + *
> > + * WARNING: This is test code. It works only with xen page size == 4096
> > + */
> > + uint64_t size;
> > + int page_offset;
> > + int num_pages;
> > + int order;
> > + int entries_on_page = 0;
> > + paddr_t gaddr;
> > + mfn_t guest_mfn;
> > + struct {
> > + uint64_t pages_list[PAGELIST_ENTRIES_PER_PAGE];
> > + uint64_t next_page_data;
> > + } *pages_data_guest, *pages_data_xen, *pages_data_xen_start;
> > +
> > + page_offset = param->u.tmem.buf_ptr & (OPTEE_MSG_NONCONTIG_PAGE_SIZE -
> > 1);
> > +
> > + size = ROUNDUP(param->u.tmem.size + page_offset,
> > + OPTEE_MSG_NONCONTIG_PAGE_SIZE);
> > +
> > + num_pages = DIV_ROUND_UP(size, OPTEE_MSG_NONCONTIG_PAGE_SIZE);
> > +
> > + order = get_order_from_bytes(get_pages_list_size(num_pages));
> > +
> > + pages_data_xen_start = alloc_xenheap_pages(order, 0);
> > + if (!pages_data_xen_start)
> > + return false;
> > +
> > + gaddr = param->u.tmem.buf_ptr & ~(OPTEE_MSG_NONCONTIG_PAGE_SIZE - 1);
> > + guest_mfn = lookup_guest_ram_addr(gaddr);
> > + if ( mfn_eq(guest_mfn, INVALID_MFN) )
> > + goto err_free;
> > +
> > + pages_data_guest = map_domain_page(guest_mfn);
> > + if (!pages_data_guest)
> > + goto err_free;
> > +
> > + pages_data_xen = pages_data_xen_start;
> > + while ( num_pages ) {
> > + mfn_t entry_mfn = lookup_guest_ram_addr(
> > + pages_data_guest->pages_list[entries_on_page]);
> > +
> > + if ( mfn_eq(entry_mfn, INVALID_MFN) )
> > + goto err_unmap;
> > +
> > + pages_data_xen->pages_list[entries_on_page] =
> > mfn_to_maddr(entry_mfn);
> > + entries_on_page++;
> > +
> > + if ( entries_on_page == PAGELIST_ENTRIES_PER_PAGE ) {
> > + pages_data_xen->next_page_data = virt_to_maddr(pages_data_xen
> > + 1);
> > + pages_data_xen++;
> > + gaddr = pages_data_guest->next_page_data;
> > + unmap_domain_page(pages_data_guest);
> > + guest_mfn = lookup_guest_ram_addr(gaddr);
> > + if ( mfn_eq(guest_mfn, INVALID_MFN) )
> > + goto err_free;
> > +
> > + pages_data_guest = map_domain_page(guest_mfn);
> > + if ( !pages_data_guest )
> > + goto err_free;
> > + /* Roll over to the next page */
> > + entries_on_page = 0;
> > + }
> > + num_pages--;
> > + }
> > +
> > + unmap_domain_page(pages_data_guest);
> > +
> > + param->u.tmem.buf_ptr = virt_to_maddr(pages_data_xen_start) |
> > page_offset;
> > +
> > + ctx->non_contig[idx] = pages_data_xen_start;
> > + ctx->non_contig_order[idx] = order;
> > +
> > + unmap_domain_page(pages_data_guest);
> > + return true;
> > +
> > +err_unmap:
> > + unmap_domain_page(pages_data_guest);
> > +err_free:
> > + free_xenheap_pages(pages_data_xen_start, order);
> > + return false;
> > +}
> > +
> > +static bool translate_params(struct std_call_ctx *ctx)
> > +{
> > + unsigned int i;
> > + uint32_t attr;
> > +
> > + for ( i = 0; i < ctx->xen_arg->num_params; i++ ) {
> > + attr = ctx->xen_arg->params[i].attr;
> > +
> > + switch ( attr & OPTEE_MSG_ATTR_TYPE_MASK ) {
> > + case OPTEE_MSG_ATTR_TYPE_TMEM_INPUT:
> > + case OPTEE_MSG_ATTR_TYPE_TMEM_OUTPUT:
> > + case OPTEE_MSG_ATTR_TYPE_TMEM_INOUT:
> > + if ( attr & OPTEE_MSG_ATTR_NONCONTIG ) {
> > + if ( !translate_noncontig(ctx, ctx->xen_arg->params + i,
> > i) )
> > + return false;
> > + }
> > + else {
> > + gprintk(XENLOG_WARNING, "Guest tries to use old tmem
> > arg\n");
> > + return false;
> > + }
> > + break;
> > + case OPTEE_MSG_ATTR_TYPE_NONE:
> > + case OPTEE_MSG_ATTR_TYPE_VALUE_INPUT:
> > + case OPTEE_MSG_ATTR_TYPE_VALUE_OUTPUT:
> > + case OPTEE_MSG_ATTR_TYPE_VALUE_INOUT:
> > + case OPTEE_MSG_ATTR_TYPE_RMEM_INPUT:
> > + case OPTEE_MSG_ATTR_TYPE_RMEM_OUTPUT:
> > + case OPTEE_MSG_ATTR_TYPE_RMEM_INOUT:
> > + continue;
> > + }
> > + }
> > + return true;
> > +}
> > +
> > +/*
> > + * Copy command buffer into xen memory to:
> > + * 1) Hide translated addresses from guest
> > + * 2) Make sure that guest wouldn't change data in command buffer during
> > call
> > + */
> > +static bool copy_std_request(struct cpu_user_regs *regs,
> > + struct std_call_ctx *ctx)
> > +{
> > + paddr_t cmd_gaddr, xen_addr;
> > + mfn_t cmd_mfn;
> > +
> > + cmd_gaddr = (paddr_t)get_user_reg(regs, 1) << 32 |
> > + get_user_reg(regs, 2);
> > +
> > + /*
> > + * Command buffer should start at page boundary.
> > + * This is OP-TEE ABI requirement.
> > + */
> > + if ( cmd_gaddr & (OPTEE_MSG_NONCONTIG_PAGE_SIZE - 1) )
> > + return false;
> > +
> > + cmd_mfn = lookup_guest_ram_addr(cmd_gaddr);
> > + if ( mfn_eq(cmd_mfn, INVALID_MFN) )
> > + return false;
> > +
> > + ctx->guest_arg = map_domain_page(cmd_mfn);
> > + if ( !ctx->guest_arg )
> > + return false;
> > +
> > + ctx->xen_arg = alloc_xenheap_page();
> > + if ( !ctx->xen_arg )
> > + return false;
> > +
> > + memcpy(ctx->xen_arg, ctx->guest_arg, OPTEE_MSG_NONCONTIG_PAGE_SIZE);
> > +
> > + xen_addr = virt_to_maddr(ctx->xen_arg);
> > +
> > + set_user_reg(regs, 1, xen_addr >> 32);
> > + set_user_reg(regs, 2, xen_addr & 0xFFFFFFFF);
> > +
> > + return true;
> > +}
> > +
> > +static bool copy_std_request_back(struct cpu_user_regs *regs,
> > + struct std_call_ctx *ctx)
> > +{
> > + unsigned int i;
> > + uint32_t attr;
> > +
> > + ctx->guest_arg->ret = ctx->xen_arg->ret;
> > + ctx->guest_arg->ret_origin = ctx->xen_arg->ret_origin;
> > + ctx->guest_arg->session = ctx->xen_arg->session;
> > + for ( i = 0; i < ctx->xen_arg->num_params; i++ ) {
> > + attr = ctx->xen_arg->params[i].attr;
> > +
> > + switch ( attr & OPTEE_MSG_ATTR_TYPE_MASK ) {
> > + case OPTEE_MSG_ATTR_TYPE_TMEM_OUTPUT:
> > + case OPTEE_MSG_ATTR_TYPE_TMEM_INOUT:
> > + ctx->guest_arg->params[i].u.tmem.size =
> > + ctx->xen_arg->params[i].u.tmem.size;
> > + continue;
> > + case OPTEE_MSG_ATTR_TYPE_VALUE_OUTPUT:
> > + case OPTEE_MSG_ATTR_TYPE_VALUE_INOUT:
> > + ctx->guest_arg->params[i].u.value.a =
> > + ctx->xen_arg->params[i].u.value.a;
> > + ctx->guest_arg->params[i].u.value.b =
> > + ctx->xen_arg->params[i].u.value.b;
> > + continue;
> > + case OPTEE_MSG_ATTR_TYPE_RMEM_OUTPUT:
> > + case OPTEE_MSG_ATTR_TYPE_RMEM_INOUT:
> > + ctx->guest_arg->params[i].u.rmem.size =
> > + ctx->xen_arg->params[i].u.rmem.size;
> > + continue;
> > + case OPTEE_MSG_ATTR_TYPE_NONE:
> > + case OPTEE_MSG_ATTR_TYPE_TMEM_INPUT:
> > + case OPTEE_MSG_ATTR_TYPE_RMEM_INPUT:
> > + case OPTEE_MSG_ATTR_TYPE_VALUE_INPUT:
> > + continue;
> > + }
> > + }
> > + return true;
> > +}
> > +
> > +static bool execute_std_call(struct cpu_user_regs *regs,
> > + struct std_call_ctx *ctx)
> > +{
> > + register_t optee_ret;
> > + forward_call(regs);
> > + optee_ret = get_user_reg(regs, 0);
> > +
> > + if ( OPTEE_SMC_RETURN_IS_RPC(optee_ret) )
> > + {
> > + ctx->optee_thread_id = get_user_reg(regs, 3);
> > + ctx->rpc_op = OPTEE_SMC_RETURN_GET_RPC_FUNC(optee_ret);
> > + return true;
> > + }
> > +
> > + copy_std_request_back(regs, ctx);
> > + free_std_call_ctx(ctx);
> > +
> > + return true;
> > +}
> > +
> > +static bool handle_std_call(struct cpu_user_regs *regs)
> > +{
> > + struct std_call_ctx *ctx;
> > + bool ret;
> > +
> > + ctx = allocate_std_call_ctx();
> > +
> > + if (!ctx)
> > + return false;
> > +
> > + ctx->domid = current->domain->domain_id;
> > +
> > + ret = copy_std_request(regs, ctx);
> > + if ( !ret )
> > + goto out;
> > +
> > + /* Now we can safely examine contents of command buffer */
> > + if ( OPTEE_MSG_GET_ARG_SIZE(ctx->xen_arg->num_params) >
> > + OPTEE_MSG_NONCONTIG_PAGE_SIZE ) {
> > + ret = false;
> > + goto out;
> > + }
> > +
> > + switch ( ctx->xen_arg->cmd )
> > + {
> > + case OPTEE_MSG_CMD_OPEN_SESSION:
> > + case OPTEE_MSG_CMD_CLOSE_SESSION:
> > + case OPTEE_MSG_CMD_INVOKE_COMMAND:
> > + case OPTEE_MSG_CMD_CANCEL:
> > + case OPTEE_MSG_CMD_REGISTER_SHM:
> > + case OPTEE_MSG_CMD_UNREGISTER_SHM:
> > + ret = translate_params(ctx);
> > + break;
> > + default:
> > + ret = false;
> > + }
> > +
> > + if (!ret)
> > + goto out;
> > +
> > + ret = execute_std_call(regs, ctx);
> > +
> > +out:
> > + if (!ret)
> > + free_std_call_ctx(ctx);
> > +
> > + return ret;
> > +}
> > +
> > +static void handle_rpc_cmd_alloc(struct cpu_user_regs *regs,
> > + struct std_call_ctx *ctx,
> > + struct shm *shm)
> > +{
> > + if ( shm->guest_arg->params[0].attr !=
> > (OPTEE_MSG_ATTR_TYPE_TMEM_OUTPUT |
> > + OPTEE_MSG_ATTR_NONCONTIG) )
> > + {
> > + gprintk(XENLOG_WARNING, "Invalid attrs for shared mem buffer\n");
> > + return;
> > + }
> > +
> > + /* Last entry in non_contig array is used to hold RPC-allocated buffer
> > */
> > + if ( ctx->non_contig[MAX_NONCONTIG_ENTRIES - 1] )
> > + {
> > + free_xenheap_pages(ctx->non_contig[7],
> > + ctx->non_contig_order[MAX_NONCONTIG_ENTRIES -
> > 1]);
> > + ctx->non_contig[7] = NULL;
> > + }
> > + translate_noncontig(ctx, shm->guest_arg->params + 0,
> > + MAX_NONCONTIG_ENTRIES - 1);
> > +}
> > +
> > +static void handle_rpc_cmd(struct cpu_user_regs *regs, struct std_call_ctx
> > *ctx)
> > +{
> > + struct shm *shm;
> > + uint64_t cookie;
> > +
> > + cookie = get_user_reg(regs, 1) << 32 | get_user_reg(regs, 2);
> > +
> > + shm = find_shm(cookie, current->domain->domain_id);
> > +
> > + if ( !shm )
> > + {
> > + gprintk(XENLOG_ERR, "Can't find SHM with cookie %lx\n", cookie);
> > + return;
> > + }
> > +
> > + switch (shm->guest_arg->cmd) {
> > + case OPTEE_MSG_RPC_CMD_GET_TIME:
> > + break;
> > + case OPTEE_MSG_RPC_CMD_WAIT_QUEUE:
> > + break;
> > + case OPTEE_MSG_RPC_CMD_SUSPEND:
> > + break;
> > + case OPTEE_MSG_RPC_CMD_SHM_ALLOC:
> > + handle_rpc_cmd_alloc(regs, ctx, shm);
> > + break;
> > + case OPTEE_MSG_RPC_CMD_SHM_FREE:
> > + break;
> > + default:
> > + break;
> > + }
> > +}
> > +
> > +static void handle_rpc_func_alloc(struct cpu_user_regs *regs,
> > + struct std_call_ctx *ctx)
> > +{
> > + paddr_t ptr = get_user_reg(regs, 1) << 32 | get_user_reg(regs, 2);
> > +
> > + if ( ptr & (OPTEE_MSG_NONCONTIG_PAGE_SIZE - 1) )
> > + gprintk(XENLOG_WARNING, "Domain returned invalid RPC command
> > buffer\n");
> > +
> > + if ( ptr ) {
> > + uint64_t cookie = get_user_reg(regs, 4) << 32 | get_user_reg(regs,
> > 5);
> > + struct shm *shm;
> > +
> > + shm = allocate_and_map_shm(ptr, cookie);
> > + if ( !shm )
> > + {
> > + gprintk(XENLOG_WARNING, "Failed to callocate allocate SHM\n");
> > + ptr = 0;
> > + }
> > + else
> > + ptr = mfn_to_maddr(shm->guest_mfn);
> > +
> > + set_user_reg(regs, 1, ptr >> 32);
> > + set_user_reg(regs, 2, ptr & 0xFFFFFFFF);
> > + }
> > +}
> > +
> > +static bool handle_rpc(struct cpu_user_regs *regs)
> > +{
> > + struct std_call_ctx *ctx;
> > +
> > + int optee_thread_id = get_user_reg(regs, 3);
> > +
> > + ctx = find_ctx(optee_thread_id, current->domain->domain_id);
> > +
> > + if (!ctx)
> > + return false;
> > +
> > + switch ( ctx->rpc_op ) {
> > + case OPTEE_SMC_RPC_FUNC_ALLOC:
> > + handle_rpc_func_alloc(regs, ctx);
> > + break;
> > + case OPTEE_SMC_RPC_FUNC_FREE:
> > + {
> > + uint64_t cookie = get_user_reg(regs, 1) << 32 | get_user_reg(regs,
> > 2);
> > + free_shm(cookie, current->domain->domain_id);
> > + break;
> > + }
> > + case OPTEE_SMC_RPC_FUNC_FOREIGN_INTR:
> > + break;
> > + case OPTEE_SMC_RPC_FUNC_CMD:
> > + handle_rpc_cmd(regs, ctx);
> > + break;
> > + }
> > +
> > + return execute_std_call(regs, ctx);
> > +}
> > +
> > +static bool handle_get_shm_config(struct cpu_user_regs *regs)
> > +{
> > + paddr_t shm_start;
> > + size_t shm_size;
> > + int rc;
> > +
> > + /* Give all static SHM region to the hardware domain */
> > + if ( !is_hardware_domain(current->domain) )
> > + return false;
> > +
> > + forward_call(regs);
> > +
> > + /* Return error back to the guest */
> > + if ( get_user_reg(regs, 0) != OPTEE_SMC_RETURN_OK)
> > + return true;
> > +
> > + shm_start = get_user_reg(regs, 1);
> > + shm_size = get_user_reg(regs, 2);
> > +
> > + /* HW dom is mapped 1:1 initially */
> > + rc = map_regions_p2mt(current->domain, gaddr_to_gfn(shm_start),
> > + shm_size / PAGE_SIZE,
> > + maddr_to_mfn(shm_start),
> > + p2m_ram_rw);
> > + if ( rc < 0 )
> > + {
> > + gprintk(XENLOG_INFO, "OP-TEE: Can't map static shm for Dom0:
> > %d\n", rc);
> > + set_user_reg(regs, 0, OPTEE_SMC_RETURN_ENOTAVAIL);
> > + }
> > +
> > + return true;
> > +}
> > +
> > +static bool handle_exchange_capabilities(struct cpu_user_regs *regs)
> > +{
> > + forward_call(regs);
> > +
> > + /* Return error back to the guest */
> > + if ( get_user_reg(regs, 0) != OPTEE_SMC_RETURN_OK )
> > + return true;
> > +
> > + /* Don't allow guests to work without dynamic SHM */
> > + if ( !(get_user_reg(regs, 1) & OPTEE_SMC_SEC_CAP_DYNAMIC_SHM) )
> > + set_user_reg(regs, 0, OPTEE_SMC_RETURN_ENOTAVAIL);
> > + return true;
> > +}
> > +
> > +static bool optee_handle_smc(struct cpu_user_regs *regs)
> > +{
> > +
> > + switch ( get_user_reg(regs, 0) )
> > + {
> > + case OPTEE_SMC_GET_SHM_CONFIG:
> > + return handle_get_shm_config(regs);
> > + case OPTEE_SMC_EXCHANGE_CAPABILITIES:
> > + return handle_exchange_capabilities(regs);
> > + case OPTEE_SMC_CALL_WITH_ARG:
> > + return handle_std_call(regs);
> > + case OPTEE_SMC_CALL_RETURN_FROM_RPC:
> > + return handle_rpc(regs);
> > + default:
> > + return forward_call(regs);
> > + }
> > + return false;
> > +}
> > +
> > +static void optee_remove(void)
> > +{
> > +}
> > +
> > +static const struct tee_mediator_ops optee_ops =
> > +{
> > + .init = optee_init,
> > + .domain_create = optee_domain_create,
> > + .domain_destroy = optee_domain_destroy,
> > + .handle_smc = optee_handle_smc,
> > + .remove = optee_remove,
> > +};
> > +
> > +REGISTER_TEE_MEDIATOR(optee, "OP-TEE", OPTEE_UID, &optee_ops);
> > +
> > +/*
> > + * Local variables:
> > + * mode: C
> > + * c-file-style: "BSD"
> > + * c-basic-offset: 4
> > + * indent-tabs-mode: nil
> > + * End:
> > + */
> > diff --git a/xen/arch/arm/tee/optee_smc.h b/xen/arch/arm/tee/optee_smc.h
> > index 92f4d54..2e9df34 100644
> > --- a/xen/arch/arm/tee/optee_smc.h
> > +++ b/xen/arch/arm/tee/optee_smc.h
> > @@ -305,6 +305,56 @@ struct optee_smc_disable_shm_cache_result {
> > OPTEE_SMC_FAST_CALL_VAL(OPTEE_SMC_FUNCID_ENABLE_SHM_CACHE)
> >
> > /*
> > + * Inform OP-TEE about a new virtual machine
> > + *
> > + * Hypervisor issues this call during virtual machine (guest) creation.
> > + * OP-TEE records VM_ID of new virtual machine and makes self ready
> > + * to receive requests from it.
> > + *
> > + * Call requests usage:
> > + * a0 SMC Function ID, OPTEE_SMC_VM_CREATED
> > + * a1 VM_ID of newly created virtual machine
> > + * a2-6 Not used
> > + * a7 Hypervisor Client ID register. Must be 0, because only
> > hypervisor
> > + * can issue this call
> > + *
> > + * Normal return register usage:
> > + * a0 OPTEE_SMC_RETURN_OK
> > + * a1-7 Preserved
> > + *
> > + * Error return:
> > + * a0 OPTEE_SMC_RETURN_ENOTAVAIL OP-TEE has no resources for
> > + * another VM
> > + * a1-7 Preserved
> > + *
> > + */
> > +#define OPTEE_SMC_FUNCID_VM_CREATED 13
> > +#define OPTEE_SMC_VM_CREATED \
> > + OPTEE_SMC_FAST_CALL_VAL(OPTEE_SMC_FUNCID_VM_CREATED)
> > +
> > +/*
> > + * Inform OP-TEE about shutdown of a virtual machine
> > + *
> > + * Hypervisor issues this call during virtual machine (guest) destruction.
> > + * OP-TEE will clean up all resources associated with this VM.
> > + *
> > + * Call requests usage:
> > + * a0 SMC Function ID, OPTEE_SMC_VM_DESTROYED
> > + * a1 VM_ID of virtual machine being shutted down
> > + * a2-6 Not used
> > + * a7 Hypervisor Client ID register. Must be 0, because only
> > hypervisor
> > + * can issue this call
> > + *
> > + * Normal return register usage:
> > + * a0 OPTEE_SMC_RETURN_OK
> > + * a1-7 Preserved
> > + *
> > + */
> > +#define OPTEE_SMC_FUNCID_VM_DESTROYED 14
> > +#define OPTEE_SMC_VM_DESTROYED \
> > + OPTEE_SMC_FAST_CALL_VAL(OPTEE_SMC_FUNCID_VM_DESTROYED)
> > +
> > +/*
> > * Resume from RPC (for example after processing a foreign interrupt)
> > *
> > * Call register usage:
> > --
> > 2.7.4
> >
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxxxxxxxxx
> > https://lists.xenproject.org/mailman/listinfo/xen-devel
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