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Date: Fri, 15 Jul 2022 12:29:54 -0700
From: Peter Gonda <pgonda@...gle.com>
To: kvm@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, marcorr@...gle.com,
seanjc@...gle.com, michael.roth@....com, thomas.lendacky@....com,
joro@...tes.org, mizhang@...gle.com, pbonzini@...hat.com,
Peter Gonda <pgonda@...gle.com>
Subject: [RFC V1 08/10] KVM: selftests: Make ucall work with encrypted guests
Add support for encrypted, SEV, guests in the ucall framework. If
encryption is enabled set up a pool of ucall structs in the guests'
shared memory region. This was suggested in the thread on "[RFC PATCH
00/10] KVM: selftests: Add support for test-selectable ucall
implementations". Using a listed as suggested there doesn't work well
because the list is setup using HVAs not GVAs so use a bitmap + array
solution instead to get the same pool result.
Suggested-by:Sean Christopherson <seanjc@...gle.com>
Signed-off-by: Peter Gonda <pgonda@...gle.com>
---
tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/include/kvm_util_base.h | 30 +++--
.../selftests/kvm/include/ucall_common.h | 14 +--
.../testing/selftests/kvm/lib/ucall_common.c | 115 ++++++++++++++++--
.../testing/selftests/kvm/lib/x86_64/ucall.c | 2 +-
5 files changed, 134 insertions(+), 28 deletions(-)
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 61e85892dd9b..3d9f2a017389 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -47,6 +47,7 @@ LIBKVM += lib/rbtree.c
LIBKVM += lib/sparsebit.c
LIBKVM += lib/test_util.c
LIBKVM += lib/ucall_common.c
+LIBKVM += $(top_srcdir)/tools/lib/find_bit.c
LIBKVM_x86_64 += lib/x86_64/apic.c
LIBKVM_x86_64 += lib/x86_64/handlers.S
diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
index 60b604ac9fa9..77aff2356d64 100644
--- a/tools/testing/selftests/kvm/include/kvm_util_base.h
+++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
@@ -65,6 +65,7 @@ struct userspace_mem_regions {
/* Memory encryption policy/configuration. */
struct vm_memcrypt {
bool enabled;
+ bool encrypted;
int8_t enc_by_default;
bool has_enc_bit;
int8_t enc_bit;
@@ -99,6 +100,8 @@ struct kvm_vm {
int stats_fd;
struct kvm_stats_header stats_header;
struct kvm_stats_desc *stats_desc;
+
+ struct list_head ucall_list;
};
@@ -141,21 +144,21 @@ enum vm_guest_mode {
extern enum vm_guest_mode vm_mode_default;
-#define VM_MODE_DEFAULT vm_mode_default
-#define MIN_PAGE_SHIFT 12U
-#define ptes_per_page(page_size) ((page_size) / 8)
+#define VM_MODE_DEFAULT vm_mode_default
+#define MIN_PAGE_SHIFT 12U
+#define ptes_per_page(page_size) ((page_size) / 8)
#elif defined(__x86_64__)
-#define VM_MODE_DEFAULT VM_MODE_PXXV48_4K
-#define MIN_PAGE_SHIFT 12U
-#define ptes_per_page(page_size) ((page_size) / 8)
+#define VM_MODE_DEFAULT VM_MODE_PXXV48_4K
+#define MIN_PAGE_SHIFT 12U
+#define ptes_per_page(page_size) ((page_size) / 8)
#elif defined(__s390x__)
-#define VM_MODE_DEFAULT VM_MODE_P44V64_4K
-#define MIN_PAGE_SHIFT 12U
-#define ptes_per_page(page_size) ((page_size) / 16)
+#define VM_MODE_DEFAULT VM_MODE_P44V64_4K
+#define MIN_PAGE_SHIFT 12U
+#define ptes_per_page(page_size) ((page_size) / 16)
#elif defined(__riscv)
@@ -163,9 +166,9 @@ extern enum vm_guest_mode vm_mode_default;
#error "RISC-V 32-bit kvm selftests not supported"
#endif
-#define VM_MODE_DEFAULT VM_MODE_P40V48_4K
-#define MIN_PAGE_SHIFT 12U
-#define ptes_per_page(page_size) ((page_size) / 8)
+#define VM_MODE_DEFAULT VM_MODE_P40V48_4K
+#define MIN_PAGE_SHIFT 12U
+#define ptes_per_page(page_size) ((page_size) / 8)
#endif
@@ -802,6 +805,9 @@ vm_paddr_t addr_arch_gva2gpa(struct kvm_vm *vm, vm_vaddr_t gva);
static inline vm_paddr_t addr_gva2gpa(struct kvm_vm *vm, vm_vaddr_t gva)
{
+ TEST_ASSERT(
+ !vm->memcrypt.encrypted,
+ "Encrypted guests have their page tables encrypted so gva2* conversions are not possible.");
return addr_arch_gva2gpa(vm, gva);
}
diff --git a/tools/testing/selftests/kvm/include/ucall_common.h b/tools/testing/selftests/kvm/include/ucall_common.h
index cb9b37282701..d8ac16a68c0a 100644
--- a/tools/testing/selftests/kvm/include/ucall_common.h
+++ b/tools/testing/selftests/kvm/include/ucall_common.h
@@ -21,6 +21,10 @@ enum {
struct ucall {
uint64_t cmd;
uint64_t args[UCALL_MAX_ARGS];
+
+ /* For encrypted guests. */
+ uint64_t idx;
+ struct ucall *hva;
};
void ucall_arch_init(struct kvm_vm *vm, void *arg);
@@ -31,15 +35,9 @@ void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu);
void ucall(uint64_t cmd, int nargs, ...);
uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc);
-static inline void ucall_init(struct kvm_vm *vm, void *arg)
-{
- ucall_arch_init(vm, arg);
-}
+void ucall_init(struct kvm_vm *vm, void *arg);
-static inline void ucall_uninit(struct kvm_vm *vm)
-{
- ucall_arch_uninit(vm);
-}
+void ucall_uninit(struct kvm_vm *vm);
#define GUEST_SYNC_ARGS(stage, arg1, arg2, arg3, arg4) \
ucall(UCALL_SYNC, 6, "hello", stage, arg1, arg2, arg3, arg4)
diff --git a/tools/testing/selftests/kvm/lib/ucall_common.c b/tools/testing/selftests/kvm/lib/ucall_common.c
index c488ed23d0dd..8e660b10f9b2 100644
--- a/tools/testing/selftests/kvm/lib/ucall_common.c
+++ b/tools/testing/selftests/kvm/lib/ucall_common.c
@@ -1,22 +1,123 @@
// SPDX-License-Identifier: GPL-2.0-only
#include "kvm_util.h"
+#include "linux/types.h"
+#include "linux/bitmap.h"
+#include "linux/bitops.h"
+#include "linux/atomic.h"
+
+struct ucall_header {
+ DECLARE_BITMAP(in_use, KVM_MAX_VCPUS);
+ struct ucall ucalls[KVM_MAX_VCPUS];
+};
+
+static bool encrypted_guest;
+static struct ucall_header *ucall_hdr;
+
+void ucall_init(struct kvm_vm *vm, void *arg)
+{
+ struct ucall *uc;
+ struct ucall_header *hdr;
+ vm_vaddr_t vaddr;
+ int i;
+
+ encrypted_guest = vm->memcrypt.enabled;
+ sync_global_to_guest(vm, encrypted_guest);
+ if (!encrypted_guest)
+ goto out;
+
+ TEST_ASSERT(!ucall_hdr,
+ "Only a single encrypted guest at a time for ucalls.");
+ vaddr = vm_vaddr_alloc_shared(vm, sizeof(*hdr), vm->page_size);
+ hdr = (struct ucall_header *)addr_gva2hva(vm, vaddr);
+ memset(hdr, 0, sizeof(*hdr));
+
+ for (i = 0; i < KVM_MAX_VCPUS; ++i) {
+ uc = &hdr->ucalls[i];
+ uc->hva = uc;
+ uc->idx = i;
+ }
+
+ ucall_hdr = (struct ucall_header *)vaddr;
+ sync_global_to_guest(vm, ucall_hdr);
+
+out:
+ ucall_arch_init(vm, arg);
+}
+
+void ucall_uninit(struct kvm_vm *vm)
+{
+ encrypted_guest = false;
+ ucall_hdr = NULL;
+
+ ucall_arch_uninit(vm);
+}
+
+static struct ucall *ucall_alloc(void)
+{
+ struct ucall *uc = NULL;
+ int i;
+
+ if (!encrypted_guest)
+ goto out;
+
+ for (i = 0; i < KVM_MAX_VCPUS; ++i) {
+ if (atomic_test_and_set_bit(i, ucall_hdr->in_use))
+ continue;
+
+ uc = &ucall_hdr->ucalls[i];
+ }
+
+out:
+ return uc;
+}
+
+static void ucall_free(struct ucall *uc)
+{
+ if (!encrypted_guest)
+ return;
+
+ clear_bit(uc->idx, ucall_hdr->in_use);
+}
+
+static vm_vaddr_t get_ucall_addr(struct ucall *uc)
+{
+ if (encrypted_guest)
+ return (vm_vaddr_t)uc->hva;
+
+ return (vm_vaddr_t)uc;
+}
void ucall(uint64_t cmd, int nargs, ...)
{
- struct ucall uc = {
- .cmd = cmd,
- };
+ struct ucall *uc;
+ struct ucall tmp;
va_list va;
int i;
+ uc = ucall_alloc();
+ if (!uc)
+ uc = &tmp;
+
+ uc->cmd = cmd;
+
nargs = min(nargs, UCALL_MAX_ARGS);
va_start(va, nargs);
for (i = 0; i < nargs; ++i)
- uc.args[i] = va_arg(va, uint64_t);
+ uc->args[i] = va_arg(va, uint64_t);
va_end(va);
- ucall_arch_do_ucall((vm_vaddr_t)&uc);
+ ucall_arch_do_ucall(get_ucall_addr(uc));
+
+ ucall_free(uc);
+}
+
+void *get_ucall_hva(struct kvm_vm *vm, void *uc)
+{
+ if (encrypted_guest)
+ return uc;
+
+ return addr_gva2hva(vm, (vm_vaddr_t)uc);
}
uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
@@ -27,9 +128,9 @@ uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
if (!uc)
uc = &ucall;
- addr = ucall_arch_get_ucall(vcpu);
+ addr = get_ucall_hva(vcpu->vm, ucall_arch_get_ucall(vcpu));
if (addr) {
- memcpy(uc, addr, sizeof(*uc));
+ memcpy(uc, addr, sizeof(struct ucall));
vcpu_run_complete_io(vcpu);
} else {
memset(uc, 0, sizeof(*uc));
diff --git a/tools/testing/selftests/kvm/lib/x86_64/ucall.c b/tools/testing/selftests/kvm/lib/x86_64/ucall.c
index ec53a406f689..ea6b2e3a8e39 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/ucall.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/ucall.c
@@ -30,7 +30,7 @@ void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu)
struct kvm_regs regs;
vcpu_regs_get(vcpu, ®s);
- return addr_gva2hva(vcpu->vm, (vm_vaddr_t)regs.rdi);
+ return (void *)regs.rdi;
}
return NULL;
}
--
2.37.0.170.g444d1eabd0-goog
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