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BACKPORT: FROMLIST: 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.

[ qperret: BACKPORT due to context conflicts in mem_protect.c caused by
  the presense of guest-related memory transition in the android kernel
  (host_donate_guest and friends) ]

Bug: 254811097
Co-developed-by: Andrew Walbran <qwandor@google.com>
Change-Id: Ib4d404cd1d4fa11d7bf8c1d0b8ec00838a8038a0
Signed-off-by: Andrew Walbran <qwandor@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20221116170335.2341003-9-qperret@google.com
This commit is contained in:
Will Deacon
2022-11-16 17:03:31 +00:00
committed by Quentin Perret
parent 847f7e0189
commit ffa0e8607e
2 changed files with 72 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
View File

@@ -58,6 +58,7 @@ enum pkvm_component_id {
PKVM_ID_HOST,
PKVM_ID_HYP,
PKVM_ID_GUEST,
PKVM_ID_FFA,
};
extern unsigned long hyp_nr_cpus;
@@ -77,6 +78,8 @@ int __pkvm_guest_relinquish_to_host(struct pkvm_hyp_vcpu *vcpu,
int __pkvm_install_ioguard_page(struct pkvm_hyp_vcpu *hyp_vcpu, u64 ipa);
int __pkvm_remove_ioguard_page(struct pkvm_hyp_vcpu *hyp_vcpu, u64 ipa);
bool __pkvm_check_ioguard_page(struct pkvm_hyp_vcpu *hyp_vcpu);
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);

69
arch/arm64/kvm/hyp/nvhe/mem_protect.c
View File

@@ -1261,6 +1261,13 @@ static int check_share(struct pkvm_mem_share *share)
case PKVM_ID_GUEST:
ret = guest_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;
}
@@ -1298,6 +1305,13 @@ static int __do_share(struct pkvm_mem_share *share)
case PKVM_ID_GUEST:
ret = guest_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;
}
@@ -1352,6 +1366,10 @@ 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;
}
@@ -1386,6 +1404,10 @@ 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;
}
@@ -1821,6 +1843,53 @@ int __pkvm_host_donate_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu)
return ret;
}
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;
}
void hyp_poison_page(phys_addr_t phys)
{
void *addr = hyp_fixmap_map(phys);