search for: xen_sysexit

The first patch fixes Xen PV regression introduced by 32-bit rewrite. Unlike the earlier version it uses ALTERNATIVE instruction and avoids using xen_sysexit (and sysret32 in compat mode) pv ops, as suggested by Andy. As result of this patch irq_enable_sysexit and usergs_sysret32 pv ops are not used anymore by anyone and so can be removed. v2: * patch both TEST and JZ intructions with a single JMP * Add magic prefix to X86_FEATURE_XENPV comment t...

The first patch fixes Xen PV regression introduced by 32-bit rewrite. Unlike the earlier version it uses ALTERNATIVE instruction and avoids using xen_sysexit (and sysret32 in compat mode) pv ops, as suggested by Andy. As result of this patch irq_enable_sysexit and usergs_sysret32 pv ops are not used anymore by anyone and so can be removed. v2: * patch both TEST and JZ intructions with a single JMP * Add magic prefix to X86_FEATURE_XENPV comment t...

On Wed, Nov 18, 2015 at 12:06 PM, Boris Ostrovsky <boris.ostrovsky at oracle.com> wrote: > After 32-bit syscall rewrite, and specifically after commit 5f310f739b4c > ("x86/entry/32: Re-implement SYSENTER using the new C path"), the stack > frame that is passed to xen_sysexit is no longer a "standard" one (i.e. > it's not pt_regs). > > Since we end up calling xen_iret from xen_sysexit we don't need to fix > up the stack and instead follow entry_SYSENTER_32's IRET path directly > to xen_iret. > > We can do the same thing for com...

On Wed, Nov 18, 2015 at 12:06 PM, Boris Ostrovsky <boris.ostrovsky at oracle.com> wrote: > After 32-bit syscall rewrite, and specifically after commit 5f310f739b4c > ("x86/entry/32: Re-implement SYSENTER using the new C path"), the stack > frame that is passed to xen_sysexit is no longer a "standard" one (i.e. > it's not pt_regs). > > Since we end up calling xen_iret from xen_sysexit we don't need to fix > up the stack and instead follow entry_SYSENTER_32's IRET path directly > to xen_iret. > > We can do the same thing for com...

The first patch fixes Xen PV regression introduced by 32-bit rewrite. Unlike the earlier version it uses ALTERNATIVE instruction and avoids using xen_sysexit (and sysret32 in compat mode) pv ops, as suggested by Andy. (I ended up patching TEST with XOR to avoid extra NOPs, even though I said yesterday it would be wrong. It's not wrong) As result of this patch irq_enable_sysexit and usergs_sysret32 pv ops are not used anymore by anyone and so can be...

The first patch fixes Xen PV regression introduced by 32-bit rewrite. Unlike the earlier version it uses ALTERNATIVE instruction and avoids using xen_sysexit (and sysret32 in compat mode) pv ops, as suggested by Andy. (I ended up patching TEST with XOR to avoid extra NOPs, even though I said yesterday it would be wrong. It's not wrong) As result of this patch irq_enable_sysexit and usergs_sysret32 pv ops are not used anymore by anyone and so can be...

...swapgs, "swapgs"); --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -1240,10 +1240,7 @@ static const struct pv_cpu_ops xen_cpu_o .iret = xen_iret, #ifdef CONFIG_X86_64 - .usergs_sysret32 = xen_sysret32, .usergs_sysret64 = xen_sysret64, -#else - .irq_enable_sysexit = xen_sysexit, #endif .load_tr_desc = paravirt_nop, --- a/arch/x86/xen/xen-asm_32.S +++ b/arch/x86/xen/xen-asm_32.S @@ -35,20 +35,6 @@ check_events: ret /* - * We can't use sysexit directly, because we're not running in ring0. - * But we can easily fake it up using iret. Assuming xen_sysexit i...

...e36 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -1229,10 +1229,7 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = { .iret = xen_iret, #ifdef CONFIG_X86_64 - .usergs_sysret32 = xen_sysret32, .usergs_sysret64 = xen_sysret64, -#else - .irq_enable_sysexit = xen_sysexit, #endif .load_tr_desc = paravirt_nop, diff --git a/arch/x86/xen/xen-asm_32.S b/arch/x86/xen/xen-asm_32.S index fd92a64..feb6d40 100644 --- a/arch/x86/xen/xen-asm_32.S +++ b/arch/x86/xen/xen-asm_32.S @@ -35,20 +35,6 @@ check_events: ret /* - * We can't use sysexit directly, because we&...

...swapgs, "swapgs"); --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -1240,10 +1240,7 @@ static const struct pv_cpu_ops xen_cpu_o .iret = xen_iret, #ifdef CONFIG_X86_64 - .usergs_sysret32 = xen_sysret32, .usergs_sysret64 = xen_sysret64, -#else - .irq_enable_sysexit = xen_sysexit, #endif .load_tr_desc = paravirt_nop, --- a/arch/x86/xen/xen-asm_32.S +++ b/arch/x86/xen/xen-asm_32.S @@ -35,20 +35,6 @@ check_events: ret /* - * We can't use sysexit directly, because we're not running in ring0. - * But we can easily fake it up using iret. Assuming xen_sysexit i...

...t 12:06 PM, Boris Ostrovsky >> <boris.ostrovsky at oracle.com> wrote: >>> After 32-bit syscall rewrite, and specifically after commit 5f310f739b4c >>> ("x86/entry/32: Re-implement SYSENTER using the new C path"), the stack >>> frame that is passed to xen_sysexit is no longer a "standard" one (i.e. >>> it's not pt_regs). >>> >>> Since we end up calling xen_iret from xen_sysexit we don't need to fix >>> up the stack and instead follow entry_SYSENTER_32's IRET path directly >>> to xen_iret. &g...

On 11/19/2015 04:55 PM, Boris Ostrovsky wrote: > After 32-bit syscall rewrite, and specifically after commit 5f310f739b4c > ("x86/entry/32: Re-implement SYSENTER using the new C path"), the stack > frame that is passed to xen_sysexit is no longer a "standard" one (i.e. > it's not pt_regs). > > Since we end up calling xen_iret from xen_sysexit we don't need to fix > up the stack and instead follow entry_SYSENTER_32's IRET path directly > to xen_iret. > > We can do the same thing for com...

On 11/19/2015 04:55 PM, Boris Ostrovsky wrote: > After 32-bit syscall rewrite, and specifically after commit 5f310f739b4c > ("x86/entry/32: Re-implement SYSENTER using the new C path"), the stack > frame that is passed to xen_sysexit is no longer a "standard" one (i.e. > it's not pt_regs). > > Since we end up calling xen_iret from xen_sysexit we don't need to fix > up the stack and instead follow entry_SYSENTER_32's IRET path directly > to xen_iret. > > We can do the same thing for com...

..., Nov 18, 2015 at 12:06 PM, Boris Ostrovsky > <boris.ostrovsky at oracle.com> wrote: >> After 32-bit syscall rewrite, and specifically after commit 5f310f739b4c >> ("x86/entry/32: Re-implement SYSENTER using the new C path"), the stack >> frame that is passed to xen_sysexit is no longer a "standard" one (i.e. >> it's not pt_regs). >> >> Since we end up calling xen_iret from xen_sysexit we don't need to fix >> up the stack and instead follow entry_SYSENTER_32's IRET path directly >> to xen_iret. >> >> We c...

After 32-bit syscall rewrite, and specifically after commit 5f310f739b4c ("x86/entry/32: Re-implement SYSENTER using the new C path"), the stack frame that is passed to xen_sysexit is no longer a "standard" one (i.e. it's not pt_regs). Since we end up calling xen_iret from xen_sysexit we don't need to fix up the stack and instead follow entry_SYSENTER_32's IRET path directly to xen_iret. We can do the same thing for compat mode even though stack does n...

...5 22:07, Andy Lutomirski wrote: > On Thu, Nov 19, 2015 at 1:55 PM, Boris Ostrovsky > <boris.ostrovsky at oracle.com> wrote: >> The first patch fixes Xen PV regression introduced by 32-bit rewrite. Unlike the >> earlier version it uses ALTERNATIVE instruction and avoids using xen_sysexit >> (and sysret32 in compat mode) pv ops, as suggested by Andy. >> >> As result of this patch irq_enable_sysexit and usergs_sysret32 pv ops are not >> used anymore by anyone and so can be removed. > This whole series is: > > Acked-by: Andy Lutomirski <luto at kern...

...5 22:07, Andy Lutomirski wrote: > On Thu, Nov 19, 2015 at 1:55 PM, Boris Ostrovsky > <boris.ostrovsky at oracle.com> wrote: >> The first patch fixes Xen PV regression introduced by 32-bit rewrite. Unlike the >> earlier version it uses ALTERNATIVE instruction and avoids using xen_sysexit >> (and sysret32 in compat mode) pv ops, as suggested by Andy. >> >> As result of this patch irq_enable_sysexit and usergs_sysret32 pv ops are not >> used anymore by anyone and so can be removed. > This whole series is: > > Acked-by: Andy Lutomirski <luto at kern...