From: Shaoqin Huang <shaoqin.huang@xxxxxxxxx>
Provide __pkvm_hyp_donate_host() to transfer the page ownership from
hypervisor to host. This will be used later when pKVM return memory
back to host.
Signed-off-by: Shaoqin Huang <shaoqin.huang@xxxxxxxxx>
---
arch/x86/kvm/vmx/pkvm/hyp/mem_protect.c | 65 +++++++++++++++++++++++++
arch/x86/kvm/vmx/pkvm/hyp/mem_protect.h | 14 ++++++
2 files changed, 79 insertions(+)
diff --git a/arch/x86/kvm/vmx/pkvm/hyp/mem_protect.c b/arch/x86/kvm/vmx/pkvm/hyp/mem_protect.c
index b040a109f87d..fad81f91794c 100644
--- a/arch/x86/kvm/vmx/pkvm/hyp/mem_protect.c
+++ b/arch/x86/kvm/vmx/pkvm/hyp/mem_protect.c
@@ -30,6 +30,7 @@ struct pkvm_mem_trans_desc {
u64 addr;
} hyp;
};
+ u64 prot;
};
struct pkvm_mem_transition {
@@ -64,6 +65,11 @@ static int host_ept_set_owner_locked(phys_addr_t addr, u64 size, pkvm_id owner_i
return ret;
}
+static int host_ept_create_idmap_locked(u64 addr, u64 size, int pgsz_mask, u64 prot)
+{
+ return pkvm_pgtable_map(pkvm_hyp->host_vm.ept, addr, addr, size, pgsz_mask, prot);
+}
+
static int
__check_page_state_walker(struct pkvm_pgtable *pgt, unsigned long vaddr,
unsigned long vaddr_end, int level, void *ptep,
@@ -120,6 +126,14 @@ static int host_request_donation(const struct pkvm_mem_transition *tx)
return __host_check_page_state_range(addr, size, PKVM_PAGE_OWNED);
}
+static int host_ack_donation(const struct pkvm_mem_transition *tx)
+{
+ u64 addr = tx->completer.host.addr;
+ u64 size = tx->size;
+
+ return __host_check_page_state_range(addr, size, PKVM_NOPAGE);
+}
+
static int check_donation(const struct pkvm_mem_transition *tx)
{
int ret;
@@ -128,6 +142,9 @@ static int check_donation(const struct pkvm_mem_transition *tx)
case PKVM_ID_HOST:
ret = host_request_donation(tx);
break;
+ case PKVM_ID_HYP:
+ ret = 0;
+ break;
default:
ret = -EINVAL;
}
@@ -136,6 +153,9 @@ static int check_donation(const struct pkvm_mem_transition *tx)
return ret;
switch (tx->completer.id) {
+ case PKVM_ID_HOST:
+ ret = host_ack_donation(tx);
+ break;
case PKVM_ID_HYP:
ret = 0;
break;
@@ -158,6 +178,15 @@ static int host_initiate_donation(const struct pkvm_mem_transition *tx)
return host_ept_set_owner_locked(addr, size, owner_id);
}
+static int host_complete_donation(const struct pkvm_mem_transition *tx)
+{
+ u64 addr = tx->completer.host.addr;
+ u64 size = tx->size;
+ u64 prot = pkvm_mkstate(tx->completer.prot, PKVM_PAGE_OWNED);
+
+ return host_ept_create_idmap_locked(addr, size, 0, prot);
+}
+
static int __do_donate(const struct pkvm_mem_transition *tx)
{
int ret;
@@ -166,6 +195,9 @@ static int __do_donate(const struct pkvm_mem_transition *tx)
case PKVM_ID_HOST:
ret = host_initiate_donation(tx);
break;
+ case PKVM_ID_HYP:
+ ret = 0;
+ break;
default:
ret = -EINVAL;
}
@@ -174,6 +206,9 @@ static int __do_donate(const struct pkvm_mem_transition *tx)
return ret;
switch (tx->completer.id) {
+ case PKVM_ID_HOST:
+ ret = host_complete_donation(tx);
+ break;
case PKVM_ID_HYP:
ret = 0;
break;
@@ -233,3 +268,33 @@ int __pkvm_host_donate_hyp(u64 hpa, u64 size)
return ret;
}
+
+int __pkvm_hyp_donate_host(u64 hpa, u64 size)
+{
+ int ret;
+ u64 hyp_addr = (u64)__pkvm_va(hpa);
+ struct pkvm_mem_transition donation = {
+ .size = size,
+ .initiator = {
+ .id = PKVM_ID_HYP,
+ .hyp = {
+ .addr = hyp_addr,
+ },
+ },
+ .completer = {
+ .id = PKVM_ID_HOST,
+ .host = {
+ .addr = hpa,
+ },
+ .prot = HOST_EPT_DEF_MEM_PROT,
+ },
+ };
+
+ host_ept_lock();
+
+ ret = do_donate(&donation);
+
+ host_ept_unlock();
+
+ return ret;
+}
diff --git a/arch/x86/kvm/vmx/pkvm/hyp/mem_protect.h b/arch/x86/kvm/vmx/pkvm/hyp/mem_protect.h
index e7e632270688..efb3b3895f58 100644
--- a/arch/x86/kvm/vmx/pkvm/hyp/mem_protect.h
+++ b/arch/x86/kvm/vmx/pkvm/hyp/mem_protect.h
@@ -68,4 +68,18 @@ typedef u32 pkvm_id;
*/
int __pkvm_host_donate_hyp(u64 hpa, u64 size);
+/*
+ * __pkvm_hyp_donate_host() - Donate pages from hyp to host, then host can
+ * access these pages.
+ *
+ * @hpa: Start hpa of being donated pages, must be continuous.
+ * @size: The size of memory to be donated.
+ *
+ * A range of pages [hpa, hpa + size) will be donated from hyp to host. This
+ * will create mapping in host ept for these pages, and nothing to do with hyp
+ * mmu. This is paired with __pkvm_host_donate_hyp(), and same as host reclaiming
+ * these pages back.
+ */
+int __pkvm_hyp_donate_host(u64 hpa, u64 size);
+
#endif
--
2.25.1
