linux-kernel - RE: [PATCH] x86/tdx: Support vmalloc() for tdx_enc_status

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Date: Fri, 28 Jun 2024 19:24:10 +0000
From: Dexuan Cui <decui@...rosoft.com>
To: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
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Subject: RE: [PATCH] x86/tdx: Support vmalloc() for tdx_enc_status_changed()

> From: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
> Sent: Friday, June 28, 2024 3:05 AM
> To: Dexuan Cui <decui@...rosoft.com>
> >   [...]
> >  static bool tdx_enc_status_changed(unsigned long vaddr, int numpages,
>  [...]
> This patch collied with kexec changes. tdx_kexec_finish() calls
> tdx_enc_status_changed() after clearing pte, so slow_virt_to_phys()
> crashes on in.
> 
> Daxuan, could you check if the fixup below works for you on vmalloc
> addresses?
> 
> diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
> index ef8ec2425998..5e455c883bcc 100644
> --- a/arch/x86/coco/tdx/tdx.c
> +++ b/arch/x86/coco/tdx/tdx.c
> @@ -813,8 +813,15 @@ static bool tdx_enc_status_changed(unsigned
> long vaddr, int numpages, bool enc)
>  		step = PAGE_SIZE;
> 
>  	for (addr = start; addr < end; addr += step) {
> -		phys_addr_t start_pa = slow_virt_to_phys((void *)addr);
> -		phys_addr_t end_pa   = start_pa + step;
> +		phys_addr_t start_pa;
> +		phys_addr_t end_pa;
> +
> +		if (virt_addr_valid(addr))
> +			start_pa = __pa(addr);
> +		else
> +			start_pa = slow_virt_to_phys((void *)addr);
> +
> +		end_pa = start_pa + step;
> 
>  		if (!tdx_enc_status_changed_phys(start_pa, end_pa, enc))
>  			return false;
> --
>   Kiryl Shutsemau / Kirill A. Shutemov

Hi Kirill, your fixup works for me.

BTW, I just realized that virt_addr_valid() returns false for a vmalloc'd address.

Thanks,
Dexuan