Hi,
On 6/20/23 8:48 AM, Dexuan Cui wrote:
> When a TDX guest runs on Hyper-V, the hv_netvsc driver's netvsc_init_buf()
> allocates buffers using vzalloc(), and needs to share the buffers with the
> host OS by calling set_memory_decrypted(), which is not working for
> vmalloc() yet. Add the support by handling the pages one by one.
>
> Co-developed-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
> Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
> ---
Looks good to me.
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
> arch/x86/coco/tdx/tdx.c | 35 +++++++++++++++++++++++++++++------
> 1 file changed, 29 insertions(+), 6 deletions(-)
>
> Changes in v2:
> Changed tdx_enc_status_changed() in place.
>
> Changes in v3:
> No change since v2.
>
> Changes in v4:
> Added Kirill's Co-developed-by since Kirill helped to improve the
> code by adding tdx_enc_status_changed_phys().
>
> Thanks Kirill for the clarification on load_unaligned_zeropad()!
>
> Changes in v5:
> Added Kirill's Signed-off-by.
> Added Michael's Reviewed-by.
>
> Changes in v6: None.
>
> Changes in v7: None.
> Note: there was a race between set_memory_encrypted() and
> load_unaligned_zeropad(), which has been fixed by the 3 patches of
> Kirill in the x86/tdx branch of the tip tree.
>
> Changes in v8:
> Rebased to tip.git's master branch.
>
> diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
> index 0c198ab73aa7..a313d5ab42f1 100644
> --- a/arch/x86/coco/tdx/tdx.c
> +++ b/arch/x86/coco/tdx/tdx.c
> @@ -8,6 +8,7 @@
> #include <linux/export.h>
> #include <linux/io.h>
> +#include <linux/mm.h>
> #include <asm/coco.h>
> #include <asm/tdx.h>
> #include <asm/vmx.h>
> #include <asm/insn.h>
> @@ -752,6 +753,19 @@ static bool tdx_map_gpa(phys_addr_t start, phys_addr_t end, bool enc)
> return false;
> }
>
> +static bool tdx_enc_status_changed_phys(phys_addr_t start, phys_addr_t end,
> + bool enc)
> +{
> + if (!tdx_map_gpa(start, end, enc))
> + return false;
> +
> + /* shared->private conversion requires memory to be accepted before use */
> + if (enc)
> + return tdx_accept_memory(start, end);
> +
> + return true;
> +}
> +
> /*
> * Inform the VMM of the guest's intent for this physical page: shared with
> * the VMM or private to the guest. The VMM is expected to change its mapping
> @@ -759,15 +773,24 @@ static bool tdx_map_gpa(phys_addr_t start, phys_addr_t end, bool enc)
> */
> static bool tdx_enc_status_changed(unsigned long vaddr, int numpages, bool enc)
> {
> - phys_addr_t start = __pa(vaddr);
> - phys_addr_t end = __pa(vaddr + numpages * PAGE_SIZE);
> + unsigned long start = vaddr;
> + unsigned long end = start + numpages * PAGE_SIZE;
>
> - if (!tdx_map_gpa(start, end, enc))
> + if (offset_in_page(start) != 0)
> return false;
>
> - /* shared->private conversion requires memory to be accepted before use */
> - if (enc)
> - return tdx_accept_memory(start, end);
> + if (!is_vmalloc_addr((void *)start))
> + return tdx_enc_status_changed_phys(__pa(start), __pa(end), enc);
> +
> + while (start < end) {
> + phys_addr_t start_pa = slow_virt_to_phys((void *)start);
> + phys_addr_t end_pa = start_pa + PAGE_SIZE;
> +
> + if (!tdx_enc_status_changed_phys(start_pa, end_pa, enc))
> + return false;
> +
> + start += PAGE_SIZE;
> + }
>
> return true;
> }
--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer
