Re: [PATCH V6 2/7] KVM: selftests: add hooks for managing protected guest memory

[Sean Christopherson <seanjc@google.com>]

On Tue, Jan 10, 2023, Peter Gonda wrote:
> Add kvm_vm.protected metadata. Protected VMs memory, potentially
> register and other state may not be accessible to KVM. This combined
> with a new protected_phy_pages bitmap will allow the selftests to check
> if a given pages is accessible.
> 
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Sean Christopherson <seanjc@google.com>
> Cc: Vishal Annapurve <vannapurve@google.com>
> Cc: Ackerley Tng <ackerleytng@google.com>
> cc: Andrew Jones <andrew.jones@linux.dev>
> Originally-by: Michael Roth <michael.roth@amd.com>
> Signed-off-by: Peter Gonda <pgonda@google.com>
> ---
>  .../selftests/kvm/include/kvm_util_base.h        | 14 ++++++++++++--
>  tools/testing/selftests/kvm/lib/kvm_util.c       | 16 +++++++++++++---
>  2 files changed, 25 insertions(+), 5 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
> index fbc2a79369b8..015b59a0b80e 100644
> --- a/tools/testing/selftests/kvm/include/kvm_util_base.h
> +++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
> @@ -45,6 +45,7 @@ typedef uint64_t vm_vaddr_t; /* Virtual Machine (Guest) virtual address */
>  struct userspace_mem_region {
>  	struct kvm_userspace_memory_region 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;
> @@ -111,6 +112,9 @@ struct kvm_vm {
>  	vm_vaddr_t handlers;
>  	uint32_t dirty_ring_size;
>  
> +	/* VM protection enabled: SEV, etc*/
> +	bool protected;
> +
>  	/* Cache of information for binary stats interface */
>  	int stats_fd;
>  	struct kvm_stats_header stats_header;
> @@ -679,10 +683,16 @@ 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,

Two underscores please.  Ignore the terrible precedent that has been set, we're
slowly purging that crud.

> +			      vm_paddr_t paddr_min, uint32_t memslot, bool protected);

Wrap, no strong justification for running long in this case since the declaration
has already wrapped, and the definition does wrap.