[PATCH v2 10/15] KVM: arm64: Introduce wrappers for host and hyp spin lock accessors

Quentin Perret
2021-10-19T12:13:45Z

From: Will Deacon <will@kernel.org>

In preparation for adding additional locked sections for manipulating
page-tables at EL2, introduce some simple wrappers around the host and
hypervisor locks so that it's a bit easier to read and bit more difficult
to take the wrong lock (or even take them in the wrong order).

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
---
arch/arm64/kvm/hyp/nvhe/mem_protect.c | 32 ++++++++++++++++++++++-----
1 file changed, 26 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index 1f0fb0780622..c111e0fcfa0a 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -27,6 +27,26 @@ static struct hyp_pool host_s2_pool;

const u8 pkvm_hyp_id = 1;

+static void host_lock_component(void)
+{
+ hyp_spin_lock(&host_kvm.lock);
+}
+
+static void host_unlock_component(void)
+{
+ hyp_spin_unlock(&host_kvm.lock);
+}
+
+static void hyp_lock_component(void)
+{
+ hyp_spin_lock(&pkvm_pgd_lock);
+}
+
+static void hyp_unlock_component(void)
+{
+ hyp_spin_unlock(&pkvm_pgd_lock);
+}
+
static void *host_s2_zalloc_pages_exact(size_t size)
{
return hyp_alloc_pages(&host_s2_pool, get_order(size));
@@ -327,14 +347,14 @@ static int host_stage2_idmap(u64 addr)

prot = is_memory ? PKVM_HOST_MEM_PROT : PKVM_HOST_MMIO_PROT;

- hyp_spin_lock(&host_kvm.lock);
+ host_lock_component();
ret = host_stage2_adjust_range(addr, &range);
if (ret)
goto unlock;

ret = host_stage2_idmap_locked(range.start, range.end - range.start, prot);
unlock:
- hyp_spin_unlock(&host_kvm.lock);
+ host_unlock_component();

return ret;
}
@@ -358,8 +378,8 @@ int __pkvm_host_share_hyp(u64 pfn)
if (!addr_is_memory(addr))
return -EINVAL;

- hyp_spin_lock(&host_kvm.lock);
- hyp_spin_lock(&pkvm_pgd_lock);
+ host_lock_component();
+ hyp_lock_component();

ret = kvm_pgtable_get_leaf(&host_kvm.pgt, addr, &pte, NULL);
if (ret)
@@ -421,8 +441,8 @@ int __pkvm_host_share_hyp(u64 pfn)
BUG_ON(ret);

unlock:
- hyp_spin_unlock(&pkvm_pgd_lock);
- hyp_spin_unlock(&host_kvm.lock);
+ hyp_unlock_component();
+ host_unlock_component();

return ret;
}
--
2.33.0.1079.g6e70778dc9-goog