From: Quentin Perret <qperret@google.com>
To: Marc Zyngier <maz@kernel.org>, James Morse <james.morse@arm.com>,
Alexandru Elisei <alexandru.elisei@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Fuad Tabba <tabba@google.com>,
David Brazdil <dbrazdil@google.com>,
Andrew Walbran <qwandor@google.com>
Cc: linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org,
kernel-team@android.com, qperret@google.com
Subject: [PATCH v2 14/15] KVM: arm64: Expose unshare hypercall to the host
Date: Tue, 19 Oct 2021 13:13:03 +0100 [thread overview]
Message-ID: <20211019121304.2732332-15-qperret@google.com> (raw)
In-Reply-To: <20211019121304.2732332-1-qperret@google.com>
From: Will Deacon <will@kernel.org>
Introduce an unshare hypercall which can be used to unmap memory from
the hypervisor stage-1 in nVHE protected mode. This will be useful to
update the EL2 ownership state of pages during guest teardown, and
avoids keeping dangling mappings to unreferenced portions of memory.
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
---
arch/arm64/include/asm/kvm_asm.h | 1 +
arch/arm64/kvm/hyp/include/nvhe/mem_protect.h | 1 +
arch/arm64/kvm/hyp/nvhe/hyp-main.c | 8 +++++
arch/arm64/kvm/hyp/nvhe/mem_protect.c | 33 +++++++++++++++++++
4 files changed, 43 insertions(+)
diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 0167f3702c61..59c55aedb0ae 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -63,6 +63,7 @@ enum __kvm_host_smccc_func {
/* Hypercalls available after pKVM finalisation */
__KVM_HOST_SMCCC_FUNC___pkvm_host_share_hyp,
+ __KVM_HOST_SMCCC_FUNC___pkvm_host_unshare_hyp,
__KVM_HOST_SMCCC_FUNC___kvm_adjust_pc,
__KVM_HOST_SMCCC_FUNC___kvm_vcpu_run,
__KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context,
diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
index 56445586c755..80e99836eac7 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
@@ -55,6 +55,7 @@ extern const u8 pkvm_hyp_id;
int __pkvm_prot_finalize(void);
int __pkvm_host_share_hyp(u64 pfn);
+int __pkvm_host_unshare_hyp(u64 pfn);
bool addr_is_memory(phys_addr_t phys);
int host_stage2_idmap_locked(phys_addr_t addr, u64 size, 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 b096bf009144..5e2197db0d32 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -147,6 +147,13 @@ static void handle___pkvm_host_share_hyp(struct kvm_cpu_context *host_ctxt)
cpu_reg(host_ctxt, 1) = __pkvm_host_share_hyp(pfn);
}
+static void handle___pkvm_host_unshare_hyp(struct kvm_cpu_context *host_ctxt)
+{
+ DECLARE_REG(u64, pfn, host_ctxt, 1);
+
+ cpu_reg(host_ctxt, 1) = __pkvm_host_unshare_hyp(pfn);
+}
+
static void handle___pkvm_create_private_mapping(struct kvm_cpu_context *host_ctxt)
{
DECLARE_REG(phys_addr_t, phys, host_ctxt, 1);
@@ -184,6 +191,7 @@ static const hcall_t host_hcall[] = {
HANDLE_FUNC(__pkvm_prot_finalize),
HANDLE_FUNC(__pkvm_host_share_hyp),
+ HANDLE_FUNC(__pkvm_host_unshare_hyp),
HANDLE_FUNC(__kvm_adjust_pc),
HANDLE_FUNC(__kvm_vcpu_run),
HANDLE_FUNC(__kvm_flush_vm_context),
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index 205616c9f107..fc542585a964 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -757,3 +757,36 @@ int __pkvm_host_share_hyp(u64 pfn)
return ret;
}
+
+int __pkvm_host_unshare_hyp(u64 pfn)
+{
+ 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,
+ },
+ },
+ .prot = PAGE_HYP,
+ };
+
+ host_lock_component();
+ hyp_lock_component();
+
+ ret = do_unshare(&share);
+
+ hyp_unlock_component();
+ host_unlock_component();
+
+ return ret;
+}
--
2.33.0.1079.g6e70778dc9-goog
next prev parent reply other threads:[~2021-10-19 12:13 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-19 12:12 [PATCH v2 00/15] KVM: arm64: pkvm: Implement unshare hypercall Quentin Perret
2021-10-19 12:12 ` [PATCH v2 01/15] KVM: arm64: Check if running in VHE from kvm_host_owns_hyp_mappings() Quentin Perret
2021-10-19 12:12 ` [PATCH v2 02/15] KVM: arm64: Provide {get,put}_page() stubs for early hyp allocator Quentin Perret
2021-10-19 12:12 ` [PATCH v2 03/15] KVM: arm64: Refcount hyp stage-1 pgtable pages Quentin Perret
2021-10-19 12:12 ` [PATCH v2 04/15] KVM: arm64: Fixup hyp stage-1 refcount Quentin Perret
2021-10-19 12:12 ` [PATCH v2 05/15] KVM: arm64: Hook up ->page_count() for hypervisor stage-1 page-table Quentin Perret
2021-10-19 12:12 ` [PATCH v2 06/15] KVM: arm64: Implement kvm_pgtable_hyp_unmap() at EL2 Quentin Perret
2021-10-19 12:12 ` [PATCH v2 07/15] KVM: arm64: Introduce kvm_share_hyp() Quentin Perret
2021-10-21 10:07 ` David Brazdil
2021-10-19 12:12 ` [PATCH v2 08/15] KVM: arm64: pkvm: Refcount the pages shared with EL2 Quentin Perret
2021-10-19 12:12 ` [PATCH v2 09/15] KVM: arm64: Extend pkvm_page_state enumeration to handle absent pages Quentin Perret
2021-10-19 12:12 ` [PATCH v2 10/15] KVM: arm64: Introduce wrappers for host and hyp spin lock accessors Quentin Perret
2021-10-19 12:13 ` [PATCH v2 11/15] KVM: arm64: Implement do_share() helper for sharing memory Quentin Perret
2021-10-19 12:13 ` [PATCH v2 12/15] KVM: arm64: Implement __pkvm_host_share_hyp() using do_share() Quentin Perret
2021-10-19 12:13 ` [PATCH v2 13/15] KVM: arm64: Implement do_unshare() helper for unsharing memory Quentin Perret
2021-10-19 12:13 ` Quentin Perret [this message]
2021-10-19 12:13 ` [PATCH v2 15/15] KVM: arm64: pkvm: Unshare guest structs during teardown Quentin Perret
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