peterz at infradead.org
2020-Aug-07 09:39 UTC
[PATCH v3 4/7] x86/paravirt: remove 32-bit support from PARAVIRT_XXL
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 > -# endifI 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?
Jürgen Groß
2020-Aug-07 10:02 UTC
[PATCH v3 4/7] x86/paravirt: remove 32-bit support from PARAVIRT_XXL
On 07.08.20 11:39, peterz at infradead.org wrote:> 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..On x86_64 we have (without PARAVIRT_XXL): #define INTERRUPT_RETURN jmp native_iret and with PARAVIRT_XXL this is basically a jmp *pv_ops.cpu.iret which will then be patched to either jmp native_iret or jmp xen_iret. On x86_32 INTERRUPT_RETURN was just "iret" for the non-paravirt case. This is the reason for above dropping of the static patch data.> 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?We want it to stay how it is. This will let both variants (PARVIRT y/n) continue to work. Juergen
peterz at infradead.org
2020-Aug-07 10:21 UTC
[PATCH v3 4/7] x86/paravirt: remove 32-bit support from PARAVIRT_XXL
On Fri, Aug 07, 2020 at 12:02:59PM +0200, J?rgen Gro? wrote:> On 07.08.20 11:39, peterz at infradead.org wrote: > > 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.. > > On x86_64 we have (without PARAVIRT_XXL): > > #define INTERRUPT_RETURN jmp native_iret > > and with PARAVIRT_XXL this is basically a jmp *pv_ops.cpu.iret which > will then be patched to either jmp native_iret or jmp xen_iret.Ah, okay. Clearly I didn't look hard enough. Thanks!
Maybe Matching Threads
- [PATCH v3 4/7] x86/paravirt: remove 32-bit support from PARAVIRT_XXL
- [PATCH v3 4/7] x86/paravirt: remove 32-bit support from PARAVIRT_XXL
- [PATCH v3 4/7] x86/paravirt: remove 32-bit support from PARAVIRT_XXL
- [PATCH v4 1/6] x86/paravirt: remove 32-bit support from PARAVIRT_XXL
- [PATCH v3 0/7] Remove 32-bit Xen PV guest support