Re: [PATCH v3 4/7] x86/paravirt: remove 32-bit support from PARAVIRT_XXL

[peterz@xxxxxxxxxxxxx]

On Fri, Aug 07, 2020 at 10:38:23AM +0200, Juergen Gross wrote:

> -# else
> -     const unsigned char     cpu_iret[1];
> -# endif
>  };
>  
>  static const struct patch_xxl patch_data_xxl = {
> @@ -42,7 +38,6 @@ static const struct patch_xxl patch_data_xxl = {
>       .irq_save_fl            = { 0x9c, 0x58 },       // pushf; pop %[re]ax
>       .mmu_read_cr2           = { 0x0f, 0x20, 0xd0 }, // mov %cr2, %[re]ax
>       .mmu_read_cr3           = { 0x0f, 0x20, 0xd8 }, // mov %cr3, %[re]ax
> -# ifdef CONFIG_X86_64
>       .mmu_write_cr3          = { 0x0f, 0x22, 0xdf }, // mov %rdi, %cr3
>       .irq_restore_fl         = { 0x57, 0x9d },       // push %rdi; popfq
>       .cpu_wbinvd             = { 0x0f, 0x09 },       // wbinvd
> @@ -50,19 +45,11 @@ static const struct patch_xxl patch_data_xxl = {
>                                   0x48, 0x0f, 0x07 }, // swapgs; sysretq
>       .cpu_swapgs             = { 0x0f, 0x01, 0xf8 }, // swapgs
>       .mov64                  = { 0x48, 0x89, 0xf8 }, // mov %rdi, %rax
> -# else
> -     .mmu_write_cr3          = { 0x0f, 0x22, 0xd8 }, // mov %eax, %cr3
> -     .irq_restore_fl         = { 0x50, 0x9d },       // push %eax; popf
> -     .cpu_iret               = { 0xcf },             // iret
> -# endif

I was looking at x86_64 paravirt the other day and found we actually
have pv_ops.cpu.iret users there..

So we want to change the above to also patch iret on x86_64 or do we
need to fix x86_64 to not have pv-iret?