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KVM: arm64: Add FF-A helpers to share/unshare memory with secure world

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Extend pKVM's memory protection code so that we can update the host's
stage-2 page-table to track pages shared with secure world by the host
using FF-A and prevent those pages from being mapped into a guest.

Co-developed-by: Andrew Walbran <qwandor@google.com>
Signed-off-by: Andrew Walbran <qwandor@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20230523101828.7328-6-will@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This commit is contained in:
Will Deacon 2023-05-23 11:18:22 +01:00 • committed by Oliver Upton
parent 9d0c6a9af9
commit f9112eade7
2 changed files with 71 additions and 0 deletions
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3
arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
View file

@ -57,6 +57,7 @@ extern struct host_mmu host_mmu;
enum pkvm_component_id {
PKVM_ID_HOST,
PKVM_ID_HYP,
PKVM_ID_FFA,
};
extern unsigned long hyp_nr_cpus;
@ -66,6 +67,8 @@ int __pkvm_host_share_hyp(u64 pfn);
int __pkvm_host_unshare_hyp(u64 pfn);
int __pkvm_host_donate_hyp(u64 pfn, u64 nr_pages);
int __pkvm_hyp_donate_host(u64 pfn, u64 nr_pages);
int __pkvm_host_share_ffa(u64 pfn, u64 nr_pages);
int __pkvm_host_unshare_ffa(u64 pfn, u64 nr_pages);
bool addr_is_memory(phys_addr_t phys);
int host_stage2_idmap_locked(phys_addr_t addr, u64 size, enum kvm_pgtable_prot prot);

68
arch/arm64/kvm/hyp/nvhe/mem_protect.c
View file

@ -842,6 +842,13 @@ static int check_share(struct pkvm_mem_share *share)
case PKVM_ID_HYP:
ret = hyp_ack_share(completer_addr, tx, share->completer_prot);
break;
case PKVM_ID_FFA:
/*
* We only check the host; the secure side will check the other
* end when we forward the FFA call.
*/
ret = 0;
break;
default:
ret = -EINVAL;
}
@ -870,6 +877,13 @@ static int __do_share(struct pkvm_mem_share *share)
case PKVM_ID_HYP:
ret = hyp_complete_share(completer_addr, tx, share->completer_prot);
break;
case PKVM_ID_FFA:
/*
* We're not responsible for any secure page-tables, so there's
* nothing to do here.
*/
ret = 0;
break;
default:
ret = -EINVAL;
}
@ -918,6 +932,10 @@ static int check_unshare(struct pkvm_mem_share *share)
case PKVM_ID_HYP:
ret = hyp_ack_unshare(completer_addr, tx);
break;
case PKVM_ID_FFA:
/* See check_share() */
ret = 0;
break;
default:
ret = -EINVAL;
}
@ -946,6 +964,10 @@ static int __do_unshare(struct pkvm_mem_share *share)
case PKVM_ID_HYP:
ret = hyp_complete_unshare(completer_addr, tx);
break;
case PKVM_ID_FFA:
/* See __do_share() */
ret = 0;
break;
default:
ret = -EINVAL;
}
@ -1235,3 +1257,49 @@ void hyp_unpin_shared_mem(void *from, void *to)
hyp_unlock_component();
host_unlock_component();
}
int __pkvm_host_share_ffa(u64 pfn, u64 nr_pages)
{
int ret;
struct pkvm_mem_share share = {
.tx = {
.nr_pages = nr_pages,
.initiator = {
.id = PKVM_ID_HOST,
.addr = hyp_pfn_to_phys(pfn),
},
.completer = {
.id = PKVM_ID_FFA,
},
},
};
host_lock_component();
ret = do_share(&share);
host_unlock_component();
return ret;
}
int __pkvm_host_unshare_ffa(u64 pfn, u64 nr_pages)
{
int ret;
struct pkvm_mem_share share = {
.tx = {
.nr_pages = nr_pages,
.initiator = {
.id = PKVM_ID_HOST,
.addr = hyp_pfn_to_phys(pfn),
},
.completer = {
.id = PKVM_ID_FFA,
},
},
};
host_lock_component();
ret = do_unshare(&share);
host_unlock_component();
return ret;
}