[PATCH v8 04/10] KVM: selftests: Add support for allocating/managing protected guest memory
Itaru Kitayama
itaru.kitayama at linux.dev
Wed Feb 14 21:26:50 PST 2024
On Fri, Feb 02, 2024 at 04:09:10PM -0800, Sean Christopherson wrote:
> From: Peter Gonda <pgonda at google.com>
>
> Add support for differentiating between protected (a.k.a. private, a.k.a.
> encrypted) memory and normal (a.k.a. shared) memory for VMs that support
> protected guest memory, e.g. x86's SEV. Provide and manage a common
> bitmap for tracking whether a given physical page resides in protected
> memory, as support for protected memory isn't x86 specific, i.e. adding a
> arch hook would be a net negative now, and in the future.
>
> Cc: Paolo Bonzini <pbonzini at redhat.com>
> Cc: Sean Christopherson <seanjc at google.com>
> Cc: Vishal Annapurve <vannapurve at google.com>
> Cc: Ackerley Tng <ackerleytng at google.com>
> cc: Andrew Jones <andrew.jones at linux.dev>
> Cc: Tom Lendacky <thomas.lendacky at amd.com>
> Cc: Michael Roth <michael.roth at amd.com>
> Originally-by: Michael Roth <michael.roth at amd.com>
> Signed-off-by: Peter Gonda <pgonda at google.com>
> Co-developed-by: Sean Christopherson <seanjc at google.com>
> Signed-off-by: Sean Christopherson <seanjc at google.com>
> ---
> .../selftests/kvm/include/kvm_util_base.h | 25 +++++++++++++++++--
> tools/testing/selftests/kvm/lib/kvm_util.c | 22 +++++++++++++---
> 2 files changed, 41 insertions(+), 6 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
> index d9dc31af2f96..a82149305349 100644
> --- a/tools/testing/selftests/kvm/include/kvm_util_base.h
> +++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
> @@ -46,6 +46,7 @@ typedef uint64_t vm_vaddr_t; /* Virtual Machine (Guest) virtual address */
> struct userspace_mem_region {
> struct kvm_userspace_memory_region2 region;
> struct sparsebit *unused_phy_pages;
> + struct sparsebit *protected_phy_pages;
> int fd;
> off_t offset;
> enum vm_mem_backing_src_type backing_src_type;
> @@ -573,6 +574,13 @@ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
> uint64_t guest_paddr, uint32_t slot, uint64_t npages,
> uint32_t flags, int guest_memfd_fd, uint64_t guest_memfd_offset);
>
> +#ifndef vm_arch_has_protected_memory
> +static inline bool vm_arch_has_protected_memory(struct kvm_vm *vm)
> +{
> + return false;
> +}
> +#endif
> +
> void vm_mem_region_set_flags(struct kvm_vm *vm, uint32_t slot, uint32_t flags);
> void vm_mem_region_move(struct kvm_vm *vm, uint32_t slot, uint64_t new_gpa);
> void vm_mem_region_delete(struct kvm_vm *vm, uint32_t slot);
> @@ -836,10 +844,23 @@ const char *exit_reason_str(unsigned int exit_reason);
>
> vm_paddr_t vm_phy_page_alloc(struct kvm_vm *vm, vm_paddr_t paddr_min,
> uint32_t memslot);
> -vm_paddr_t vm_phy_pages_alloc(struct kvm_vm *vm, size_t num,
> - vm_paddr_t paddr_min, uint32_t memslot);
> +vm_paddr_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t num,
> + vm_paddr_t paddr_min, uint32_t memslot,
> + bool protected);
> vm_paddr_t vm_alloc_page_table(struct kvm_vm *vm);
>
> +static inline vm_paddr_t vm_phy_pages_alloc(struct kvm_vm *vm, size_t num,
> + vm_paddr_t paddr_min, uint32_t memslot)
> +{
> + /*
> + * By default, allocate memory as protected for VMs that support
> + * protected memory, as the majority of memory for such VMs is
> + * protected, i.e. using shared memory is effectively opt-in.
> + */
> + return __vm_phy_pages_alloc(vm, num, paddr_min, memslot,
> + vm_arch_has_protected_memory(vm));
> +}
> +
> /*
> * ____vm_create() does KVM_CREATE_VM and little else. __vm_create() also
> * loads the test binary into guest memory and creates an IRQ chip (x86 only).
> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> index a53caf81eb87..ea677aa019ef 100644
> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> @@ -717,6 +717,7 @@ static void __vm_mem_region_delete(struct kvm_vm *vm,
> vm_ioctl(vm, KVM_SET_USER_MEMORY_REGION2, ®ion->region);
>
> sparsebit_free(®ion->unused_phy_pages);
> + sparsebit_free(®ion->protected_phy_pages);
> ret = munmap(region->mmap_start, region->mmap_size);
> TEST_ASSERT(!ret, __KVM_SYSCALL_ERROR("munmap()", ret));
> if (region->fd >= 0) {
> @@ -1098,6 +1099,8 @@ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
> }
>
> region->unused_phy_pages = sparsebit_alloc();
> + if (vm_arch_has_protected_memory(vm))
> + region->protected_phy_pages = sparsebit_alloc();
> sparsebit_set_num(region->unused_phy_pages,
> guest_paddr >> vm->page_shift, npages);
> region->region.slot = slot;
> @@ -1924,6 +1927,10 @@ void vm_dump(FILE *stream, struct kvm_vm *vm, uint8_t indent)
> region->host_mem);
> fprintf(stream, "%*sunused_phy_pages: ", indent + 2, "");
> sparsebit_dump(stream, region->unused_phy_pages, 0);
> + if (region->protected_phy_pages) {
> + fprintf(stream, "%*sprotected_phy_pages: ", indent + 2, "");
> + sparsebit_dump(stream, region->protected_phy_pages, 0);
> + }
> }
> fprintf(stream, "%*sMapped Virtual Pages:\n", indent, "");
> sparsebit_dump(stream, vm->vpages_mapped, indent + 2);
> @@ -2025,6 +2032,7 @@ const char *exit_reason_str(unsigned int exit_reason)
> * num - number of pages
> * paddr_min - Physical address minimum
> * memslot - Memory region to allocate page from
> + * protected - True if the pages will be used as protected/private memory
> *
> * Output Args: None
> *
> @@ -2036,8 +2044,9 @@ const char *exit_reason_str(unsigned int exit_reason)
> * and their base address is returned. A TEST_ASSERT failure occurs if
> * not enough pages are available at or above paddr_min.
> */
> -vm_paddr_t vm_phy_pages_alloc(struct kvm_vm *vm, size_t num,
> - vm_paddr_t paddr_min, uint32_t memslot)
> +vm_paddr_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t num,
> + vm_paddr_t paddr_min, uint32_t memslot,
> + bool protected)
> {
> struct userspace_mem_region *region;
> sparsebit_idx_t pg, base;
> @@ -2050,8 +2059,10 @@ vm_paddr_t vm_phy_pages_alloc(struct kvm_vm *vm, size_t num,
> paddr_min, vm->page_size);
>
> region = memslot2region(vm, memslot);
> + TEST_ASSERT(!protected || region->protected_phy_pages,
> + "Region doesn't support protected memory");
> +
> base = pg = paddr_min >> vm->page_shift;
> -
> do {
> for (; pg < base + num; ++pg) {
> if (!sparsebit_is_set(region->unused_phy_pages, pg)) {
> @@ -2070,8 +2081,11 @@ vm_paddr_t vm_phy_pages_alloc(struct kvm_vm *vm, size_t num,
> abort();
> }
>
> - for (pg = base; pg < base + num; ++pg)
> + for (pg = base; pg < base + num; ++pg) {
> sparsebit_clear(region->unused_phy_pages, pg);
> + if (protected)
> + sparsebit_set(region->protected_phy_pages, pg);
> + }
>
> return base * vm->page_size;
> }
Reviewed-by: Itaru Kitayama <itaru.kitayama at fujitsu.com>
> --
> 2.43.0.594.gd9cf4e227d-goog
>
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