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Message-ID: <20250110121936.1559655-3-qperret@google.com>
Date: Fri, 10 Jan 2025 12:19:35 +0000
From: Quentin Perret <qperret@...gle.com>
To: Marc Zyngier <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>,
Joey Gouly <joey.gouly@....com>, Suzuki K Poulose <suzuki.poulose@....com>,
Zenghui Yu <yuzenghui@...wei.com>, Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>
Cc: Fuad Tabba <tabba@...gle.com>, Vincent Donnefort <vdonnefort@...gle.com>,
linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev,
linux-kernel@...r.kernel.org
Subject: [PATCH 2/3] KVM: arm64: Drop pkvm_mem_transition for host/hyp sharing
Simplify the __pkvm_host_{un}share_hyp() paths by not using the
pkvm_mem_transition machinery. As there are the last users of the
do_share()/do_unshare(), remove all the now-unused code as well.
No functional changes intended.
Signed-off-by: Quentin Perret <qperret@...gle.com>
---
arch/arm64/kvm/hyp/nvhe/mem_protect.c | 319 +++-----------------------
1 file changed, 34 insertions(+), 285 deletions(-)
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index 3a3d9fcbc508..cd8d233b9527 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -685,36 +685,6 @@ static int host_request_owned_transition(u64 *completer_addr,
return __host_check_page_state_range(addr, size, PKVM_PAGE_OWNED);
}
-static int host_request_unshare(u64 *completer_addr,
- const struct pkvm_mem_transition *tx)
-{
- u64 size = tx->nr_pages * PAGE_SIZE;
- u64 addr = tx->initiator.addr;
-
- *completer_addr = tx->initiator.host.completer_addr;
- return __host_check_page_state_range(addr, size, PKVM_PAGE_SHARED_OWNED);
-}
-
-static int host_initiate_share(u64 *completer_addr,
- const struct pkvm_mem_transition *tx)
-{
- u64 size = tx->nr_pages * PAGE_SIZE;
- u64 addr = tx->initiator.addr;
-
- *completer_addr = tx->initiator.host.completer_addr;
- return __host_set_page_state_range(addr, size, PKVM_PAGE_SHARED_OWNED);
-}
-
-static int host_initiate_unshare(u64 *completer_addr,
- const struct pkvm_mem_transition *tx)
-{
- u64 size = tx->nr_pages * PAGE_SIZE;
- u64 addr = tx->initiator.addr;
-
- *completer_addr = tx->initiator.host.completer_addr;
- return __host_set_page_state_range(addr, size, PKVM_PAGE_OWNED);
-}
-
static int host_initiate_donation(u64 *completer_addr,
const struct pkvm_mem_transition *tx)
{
@@ -802,31 +772,6 @@ static bool __hyp_ack_skip_pgtable_check(const struct pkvm_mem_transition *tx)
tx->initiator.id != PKVM_ID_HOST);
}
-static int hyp_ack_share(u64 addr, const struct pkvm_mem_transition *tx,
- enum kvm_pgtable_prot perms)
-{
- u64 size = tx->nr_pages * PAGE_SIZE;
-
- if (perms != PAGE_HYP)
- return -EPERM;
-
- if (__hyp_ack_skip_pgtable_check(tx))
- return 0;
-
- return __hyp_check_page_state_range(addr, size, PKVM_NOPAGE);
-}
-
-static int hyp_ack_unshare(u64 addr, const struct pkvm_mem_transition *tx)
-{
- u64 size = tx->nr_pages * PAGE_SIZE;
-
- if (tx->initiator.id == PKVM_ID_HOST && hyp_page_count((void *)addr))
- return -EBUSY;
-
- return __hyp_check_page_state_range(addr, size,
- PKVM_PAGE_SHARED_BORROWED);
-}
-
static int hyp_ack_donation(u64 addr, const struct pkvm_mem_transition *tx)
{
u64 size = tx->nr_pages * PAGE_SIZE;
@@ -837,24 +782,6 @@ static int hyp_ack_donation(u64 addr, const struct pkvm_mem_transition *tx)
return __hyp_check_page_state_range(addr, size, PKVM_NOPAGE);
}
-static int hyp_complete_share(u64 addr, const struct pkvm_mem_transition *tx,
- enum kvm_pgtable_prot perms)
-{
- void *start = (void *)addr, *end = start + (tx->nr_pages * PAGE_SIZE);
- enum kvm_pgtable_prot prot;
-
- prot = pkvm_mkstate(perms, PKVM_PAGE_SHARED_BORROWED);
- return pkvm_create_mappings_locked(start, end, prot);
-}
-
-static int hyp_complete_unshare(u64 addr, const struct pkvm_mem_transition *tx)
-{
- u64 size = tx->nr_pages * PAGE_SIZE;
- int ret = kvm_pgtable_hyp_unmap(&pkvm_pgtable, addr, size);
-
- return (ret != size) ? -EFAULT : 0;
-}
-
static int hyp_complete_donation(u64 addr,
const struct pkvm_mem_transition *tx)
{
@@ -885,180 +812,6 @@ static int __guest_check_page_state_range(struct pkvm_hyp_vcpu *vcpu, u64 addr,
return check_page_state_range(&vm->pgt, addr, size, &d);
}
-static int check_share(struct pkvm_mem_share *share)
-{
- const struct pkvm_mem_transition *tx = &share->tx;
- u64 completer_addr;
- int ret;
-
- switch (tx->initiator.id) {
- case PKVM_ID_HOST:
- ret = host_request_owned_transition(&completer_addr, tx);
- break;
- default:
- ret = -EINVAL;
- }
-
- if (ret)
- return ret;
-
- switch (tx->completer.id) {
- 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;
- }
-
- return ret;
-}
-
-static int __do_share(struct pkvm_mem_share *share)
-{
- const struct pkvm_mem_transition *tx = &share->tx;
- u64 completer_addr;
- int ret;
-
- switch (tx->initiator.id) {
- case PKVM_ID_HOST:
- ret = host_initiate_share(&completer_addr, tx);
- break;
- default:
- ret = -EINVAL;
- }
-
- if (ret)
- return ret;
-
- switch (tx->completer.id) {
- 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;
- }
-
- return ret;
-}
-
-/*
- * do_share():
- *
- * The page owner grants access to another component with a given set
- * of permissions.
- *
- * Initiator: OWNED => SHARED_OWNED
- * Completer: NOPAGE => SHARED_BORROWED
- */
-static int do_share(struct pkvm_mem_share *share)
-{
- int ret;
-
- ret = check_share(share);
- if (ret)
- return ret;
-
- return WARN_ON(__do_share(share));
-}
-
-static int check_unshare(struct pkvm_mem_share *share)
-{
- const struct pkvm_mem_transition *tx = &share->tx;
- u64 completer_addr;
- int ret;
-
- switch (tx->initiator.id) {
- case PKVM_ID_HOST:
- ret = host_request_unshare(&completer_addr, tx);
- break;
- default:
- ret = -EINVAL;
- }
-
- if (ret)
- return ret;
-
- switch (tx->completer.id) {
- 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;
- }
-
- return ret;
-}
-
-static int __do_unshare(struct pkvm_mem_share *share)
-{
- const struct pkvm_mem_transition *tx = &share->tx;
- u64 completer_addr;
- int ret;
-
- switch (tx->initiator.id) {
- case PKVM_ID_HOST:
- ret = host_initiate_unshare(&completer_addr, tx);
- break;
- default:
- ret = -EINVAL;
- }
-
- if (ret)
- return ret;
-
- switch (tx->completer.id) {
- 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;
- }
-
- return ret;
-}
-
-/*
- * do_unshare():
- *
- * The page owner revokes access from another component for a range of
- * pages which were previously shared using do_share().
- *
- * Initiator: SHARED_OWNED => OWNED
- * Completer: SHARED_BORROWED => NOPAGE
- */
-static int do_unshare(struct pkvm_mem_share *share)
-{
- int ret;
-
- ret = check_unshare(share);
- if (ret)
- return ret;
-
- return WARN_ON(__do_unshare(share));
-}
-
static int check_donation(struct pkvm_mem_donation *donation)
{
const struct pkvm_mem_transition *tx = &donation->tx;
@@ -1149,31 +902,29 @@ static int do_donate(struct pkvm_mem_donation *donation)
int __pkvm_host_share_hyp(u64 pfn)
{
+ u64 phys = hyp_pfn_to_phys(pfn);
+ void *virt = __hyp_va(phys);
+ enum kvm_pgtable_prot prot;
+ u64 size = PAGE_SIZE;
int ret;
- u64 host_addr = hyp_pfn_to_phys(pfn);
- u64 hyp_addr = (u64)__hyp_va(host_addr);
- struct pkvm_mem_share share = {
- .tx = {
- .nr_pages = 1,
- .initiator = {
- .id = PKVM_ID_HOST,
- .addr = host_addr,
- .host = {
- .completer_addr = hyp_addr,
- },
- },
- .completer = {
- .id = PKVM_ID_HYP,
- },
- },
- .completer_prot = PAGE_HYP,
- };
host_lock_component();
hyp_lock_component();
- ret = do_share(&share);
+ ret = __host_check_page_state_range(phys, size, PKVM_PAGE_OWNED);
+ if (ret)
+ goto unlock;
+ if (IS_ENABLED(CONFIG_NVHE_EL2_DEBUG)) {
+ ret = __hyp_check_page_state_range((u64)virt, size, PKVM_NOPAGE);
+ if (ret)
+ goto unlock;
+ }
+
+ prot = pkvm_mkstate(PAGE_HYP, PKVM_PAGE_SHARED_BORROWED);
+ WARN_ON(pkvm_create_mappings_locked(virt, virt + size, prot));
+ WARN_ON(__host_set_page_state_range(phys, size, PKVM_PAGE_SHARED_OWNED));
+unlock:
hyp_unlock_component();
host_unlock_component();
@@ -1182,31 +933,29 @@ int __pkvm_host_share_hyp(u64 pfn)
int __pkvm_host_unshare_hyp(u64 pfn)
{
+ u64 phys = hyp_pfn_to_phys(pfn);
+ u64 virt = (u64)__hyp_va(phys);
+ u64 size = PAGE_SIZE;
int ret;
- u64 host_addr = hyp_pfn_to_phys(pfn);
- u64 hyp_addr = (u64)__hyp_va(host_addr);
- struct pkvm_mem_share share = {
- .tx = {
- .nr_pages = 1,
- .initiator = {
- .id = PKVM_ID_HOST,
- .addr = host_addr,
- .host = {
- .completer_addr = hyp_addr,
- },
- },
- .completer = {
- .id = PKVM_ID_HYP,
- },
- },
- .completer_prot = PAGE_HYP,
- };
host_lock_component();
hyp_lock_component();
- ret = do_unshare(&share);
+ ret = __host_check_page_state_range(phys, size, PKVM_PAGE_SHARED_OWNED);
+ if (ret)
+ goto unlock;
+ ret = __hyp_check_page_state_range(virt, size, PKVM_PAGE_SHARED_BORROWED);
+ if (ret)
+ goto unlock;
+ if (hyp_page_count((void *)virt)) {
+ ret = -EBUSY;
+ goto unlock;
+ }
+
+ WARN_ON(kvm_pgtable_hyp_unmap(&pkvm_pgtable, virt, size) != size);
+ WARN_ON(__host_set_page_state_range(phys, size, PKVM_PAGE_OWNED));
+unlock:
hyp_unlock_component();
host_unlock_component();
--
2.47.1.688.g23fc6f90ad-goog
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