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Message-ID: <20250509131706.2336138-4-vdonnefort@google.com>
Date: Fri, 9 May 2025 14:16:59 +0100
From: Vincent Donnefort <vdonnefort@...gle.com>
To: maz@...nel.org, oliver.upton@...ux.dev, joey.gouly@....com,
suzuki.poulose@....com, yuzenghui@...wei.com, catalin.marinas@....com,
will@...nel.org
Cc: qperret@...gle.com, linux-arm-kernel@...ts.infradead.org,
kvmarm@...ts.linux.dev, linux-kernel@...r.kernel.org, kernel-team@...roid.com,
Vincent Donnefort <vdonnefort@...gle.com>
Subject: [PATCH v4 03/10] KVM: arm64: Add a range to __pkvm_host_share_guest()
In preparation for supporting stage-2 huge mappings for np-guest. Add a
nr_pages argument to the __pkvm_host_share_guest hypercall. This range
supports only two values: 1 or PMD_SIZE / PAGE_SIZE (that is 512 on a
4K-pages system).
Signed-off-by: Vincent Donnefort <vdonnefort@...gle.com>
diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
index 26016eb9323f..47aa7b01114f 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
@@ -39,7 +39,7 @@ 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);
-int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu,
+int __pkvm_host_share_guest(u64 pfn, u64 gfn, u64 nr_pages, struct pkvm_hyp_vcpu *vcpu,
enum kvm_pgtable_prot prot);
int __pkvm_host_unshare_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm);
int __pkvm_host_relax_perms_guest(u64 gfn, struct pkvm_hyp_vcpu *vcpu, enum kvm_pgtable_prot prot);
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index 59db9606e6e1..4d3d215955c3 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -245,7 +245,8 @@ static void handle___pkvm_host_share_guest(struct kvm_cpu_context *host_ctxt)
{
DECLARE_REG(u64, pfn, host_ctxt, 1);
DECLARE_REG(u64, gfn, host_ctxt, 2);
- DECLARE_REG(enum kvm_pgtable_prot, prot, host_ctxt, 3);
+ DECLARE_REG(u64, nr_pages, host_ctxt, 3);
+ DECLARE_REG(enum kvm_pgtable_prot, prot, host_ctxt, 4);
struct pkvm_hyp_vcpu *hyp_vcpu;
int ret = -EINVAL;
@@ -260,7 +261,7 @@ static void handle___pkvm_host_share_guest(struct kvm_cpu_context *host_ctxt)
if (ret)
goto out;
- ret = __pkvm_host_share_guest(pfn, gfn, hyp_vcpu, prot);
+ ret = __pkvm_host_share_guest(pfn, gfn, nr_pages, hyp_vcpu, prot);
out:
cpu_reg(host_ctxt, 1) = ret;
}
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index 4d269210dae0..f0f7c6f83e57 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -696,10 +696,9 @@ static enum pkvm_page_state guest_get_page_state(kvm_pte_t pte, u64 addr)
return pkvm_getstate(kvm_pgtable_stage2_pte_prot(pte));
}
-static int __guest_check_page_state_range(struct pkvm_hyp_vcpu *vcpu, u64 addr,
+static int __guest_check_page_state_range(struct pkvm_hyp_vm *vm, u64 addr,
u64 size, enum pkvm_page_state state)
{
- struct pkvm_hyp_vm *vm = pkvm_hyp_vcpu_to_hyp_vm(vcpu);
struct check_walk_data d = {
.desired = state,
.get_page_state = guest_get_page_state,
@@ -908,48 +907,81 @@ int __pkvm_host_unshare_ffa(u64 pfn, u64 nr_pages)
return ret;
}
-int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu,
+static int __guest_check_transition_size(u64 phys, u64 ipa, u64 nr_pages, u64 *size)
+{
+ if (nr_pages == 1) {
+ *size = PAGE_SIZE;
+ return 0;
+ }
+
+ /* We solely support PMD_SIZE huge-pages */
+ if (nr_pages != (1 << (PMD_SHIFT - PAGE_SHIFT)))
+ return -EINVAL;
+
+ if (!IS_ALIGNED(phys | ipa, PMD_SIZE))
+ return -EINVAL;
+
+ *size = PMD_SIZE;
+ return 0;
+}
+
+int __pkvm_host_share_guest(u64 pfn, u64 gfn, u64 nr_pages, struct pkvm_hyp_vcpu *vcpu,
enum kvm_pgtable_prot prot)
{
struct pkvm_hyp_vm *vm = pkvm_hyp_vcpu_to_hyp_vm(vcpu);
u64 phys = hyp_pfn_to_phys(pfn);
u64 ipa = hyp_pfn_to_phys(gfn);
struct hyp_page *page;
+ u64 size;
int ret;
if (prot & ~KVM_PGTABLE_PROT_RWX)
return -EINVAL;
- ret = check_range_allowed_memory(phys, phys + PAGE_SIZE);
+ ret = __guest_check_transition_size(phys, ipa, nr_pages, &size);
+ if (ret)
+ return ret;
+
+ ret = check_range_allowed_memory(phys, phys + size);
if (ret)
return ret;
host_lock_component();
guest_lock_component(vm);
- ret = __guest_check_page_state_range(vcpu, ipa, PAGE_SIZE, PKVM_NOPAGE);
+ ret = __guest_check_page_state_range(vm, ipa, size, PKVM_NOPAGE);
if (ret)
goto unlock;
- page = hyp_phys_to_page(phys);
- switch (get_host_state(page)) {
- case PKVM_PAGE_OWNED:
- WARN_ON(__host_set_page_state_range(phys, PAGE_SIZE, PKVM_PAGE_SHARED_OWNED));
- break;
- case PKVM_PAGE_SHARED_OWNED:
- if (page->host_share_guest_count)
- break;
- /* Only host to np-guest multi-sharing is tolerated */
- fallthrough;
- default:
- ret = -EPERM;
- goto unlock;
+ for_each_hyp_page(phys, size, page) {
+ switch (get_host_state(page)) {
+ case PKVM_PAGE_OWNED:
+ continue;
+ case PKVM_PAGE_SHARED_OWNED:
+ if (page->host_share_guest_count == U32_MAX) {
+ ret = -EBUSY;
+ goto unlock;
+ }
+
+ /* Only host to np-guest multi-sharing is tolerated */
+ if (page->host_share_guest_count)
+ continue;
+
+ fallthrough;
+ default:
+ ret = -EPERM;
+ goto unlock;
+ }
+ }
+
+ for_each_hyp_page(phys, size, page) {
+ set_host_state(page, PKVM_PAGE_SHARED_OWNED);
+ page->host_share_guest_count++;
}
- WARN_ON(kvm_pgtable_stage2_map(&vm->pgt, ipa, PAGE_SIZE, phys,
+ WARN_ON(kvm_pgtable_stage2_map(&vm->pgt, ipa, size, phys,
pkvm_mkstate(prot, PKVM_PAGE_SHARED_BORROWED),
&vcpu->vcpu.arch.pkvm_memcache, 0));
- page->host_share_guest_count++;
unlock:
guest_unlock_component(vm);
@@ -1170,6 +1202,9 @@ static void assert_page_state(void)
struct pkvm_hyp_vcpu *vcpu = &selftest_vcpu;
u64 phys = hyp_virt_to_phys(virt);
u64 ipa[2] = { selftest_ipa(), selftest_ipa() + PAGE_SIZE };
+ struct pkvm_hyp_vm *vm;
+
+ vm = pkvm_hyp_vcpu_to_hyp_vm(vcpu);
host_lock_component();
WARN_ON(__host_check_page_state_range(phys, size, selftest_state.host));
@@ -1180,8 +1215,8 @@ static void assert_page_state(void)
hyp_unlock_component();
guest_lock_component(&selftest_vm);
- WARN_ON(__guest_check_page_state_range(vcpu, ipa[0], size, selftest_state.guest[0]));
- WARN_ON(__guest_check_page_state_range(vcpu, ipa[1], size, selftest_state.guest[1]));
+ WARN_ON(__guest_check_page_state_range(vm, ipa[0], size, selftest_state.guest[0]));
+ WARN_ON(__guest_check_page_state_range(vm, ipa[1], size, selftest_state.guest[1]));
guest_unlock_component(&selftest_vm);
}
@@ -1219,7 +1254,7 @@ void pkvm_ownership_selftest(void *base)
assert_transition_res(-EPERM, __pkvm_host_share_ffa, pfn, 1);
assert_transition_res(-EPERM, __pkvm_host_unshare_ffa, pfn, 1);
assert_transition_res(-EPERM, hyp_pin_shared_mem, virt, virt + size);
- assert_transition_res(-EPERM, __pkvm_host_share_guest, pfn, gfn, vcpu, prot);
+ assert_transition_res(-EPERM, __pkvm_host_share_guest, pfn, gfn, 1, vcpu, prot);
assert_transition_res(-ENOENT, __pkvm_host_unshare_guest, gfn, vm);
selftest_state.host = PKVM_PAGE_OWNED;
@@ -1238,7 +1273,7 @@ void pkvm_ownership_selftest(void *base)
assert_transition_res(-EPERM, __pkvm_host_donate_hyp, pfn, 1);
assert_transition_res(-EPERM, __pkvm_host_share_ffa, pfn, 1);
assert_transition_res(-EPERM, __pkvm_hyp_donate_host, pfn, 1);
- assert_transition_res(-EPERM, __pkvm_host_share_guest, pfn, gfn, vcpu, prot);
+ assert_transition_res(-EPERM, __pkvm_host_share_guest, pfn, gfn, 1, vcpu, prot);
assert_transition_res(-ENOENT, __pkvm_host_unshare_guest, gfn, vm);
assert_transition_res(0, hyp_pin_shared_mem, virt, virt + size);
@@ -1250,7 +1285,7 @@ void pkvm_ownership_selftest(void *base)
assert_transition_res(-EPERM, __pkvm_host_donate_hyp, pfn, 1);
assert_transition_res(-EPERM, __pkvm_host_share_ffa, pfn, 1);
assert_transition_res(-EPERM, __pkvm_hyp_donate_host, pfn, 1);
- assert_transition_res(-EPERM, __pkvm_host_share_guest, pfn, gfn, vcpu, prot);
+ assert_transition_res(-EPERM, __pkvm_host_share_guest, pfn, gfn, 1, vcpu, prot);
assert_transition_res(-ENOENT, __pkvm_host_unshare_guest, gfn, vm);
hyp_unpin_shared_mem(virt, virt + size);
@@ -1269,7 +1304,7 @@ void pkvm_ownership_selftest(void *base)
assert_transition_res(-EPERM, __pkvm_host_share_hyp, pfn);
assert_transition_res(-EPERM, __pkvm_host_unshare_hyp, pfn);
assert_transition_res(-EPERM, __pkvm_hyp_donate_host, pfn, 1);
- assert_transition_res(-EPERM, __pkvm_host_share_guest, pfn, gfn, vcpu, prot);
+ assert_transition_res(-EPERM, __pkvm_host_share_guest, pfn, gfn, 1, vcpu, prot);
assert_transition_res(-ENOENT, __pkvm_host_unshare_guest, gfn, vm);
assert_transition_res(-EPERM, hyp_pin_shared_mem, virt, virt + size);
@@ -1280,8 +1315,8 @@ void pkvm_ownership_selftest(void *base)
selftest_state.host = PKVM_PAGE_SHARED_OWNED;
selftest_state.guest[0] = PKVM_PAGE_SHARED_BORROWED;
- assert_transition_res(0, __pkvm_host_share_guest, pfn, gfn, vcpu, prot);
- assert_transition_res(-EPERM, __pkvm_host_share_guest, pfn, gfn, vcpu, prot);
+ assert_transition_res(0, __pkvm_host_share_guest, pfn, gfn, 1, vcpu, prot);
+ assert_transition_res(-EPERM, __pkvm_host_share_guest, pfn, gfn, 1, vcpu, prot);
assert_transition_res(-EPERM, __pkvm_host_share_ffa, pfn, 1);
assert_transition_res(-EPERM, __pkvm_host_donate_hyp, pfn, 1);
assert_transition_res(-EPERM, __pkvm_host_share_hyp, pfn);
@@ -1290,7 +1325,7 @@ void pkvm_ownership_selftest(void *base)
assert_transition_res(-EPERM, hyp_pin_shared_mem, virt, virt + size);
selftest_state.guest[1] = PKVM_PAGE_SHARED_BORROWED;
- assert_transition_res(0, __pkvm_host_share_guest, pfn, gfn + 1, vcpu, prot);
+ assert_transition_res(0, __pkvm_host_share_guest, pfn, gfn + 1, 1, vcpu, prot);
WARN_ON(hyp_virt_to_page(virt)->host_share_guest_count != 2);
selftest_state.guest[0] = PKVM_NOPAGE;
diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
index 83a737484046..0285e2cd2e7f 100644
--- a/arch/arm64/kvm/pkvm.c
+++ b/arch/arm64/kvm/pkvm.c
@@ -347,7 +347,7 @@ int pkvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
return -EINVAL;
lockdep_assert_held_write(&kvm->mmu_lock);
- ret = kvm_call_hyp_nvhe(__pkvm_host_share_guest, pfn, gfn, prot);
+ ret = kvm_call_hyp_nvhe(__pkvm_host_share_guest, pfn, gfn, 1, prot);
if (ret) {
/* Is the gfn already mapped due to a racing vCPU? */
if (ret == -EPERM)
--
2.49.0.1015.ga840276032-goog
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