similar to: paravirt patches in -mm

Hi all, [ Change since last post: change name to ptep_modify_prot_, on the grounds that it isn't really a general pte-modification interface. ] This little series adds a new transaction-like abstraction for doing RMW updates to a pte, hooks it into paravirt_ops, and then makes use of it in Xen. The basic problem is that mprotect is very slow under Xen (up to 50x slower than native),

Hi all, [ Change since last post: change name to ptep_modify_prot_, on the grounds that it isn't really a general pte-modification interface. ] This little series adds a new transaction-like abstraction for doing RMW updates to a pte, hooks it into paravirt_ops, and then makes use of it in Xen. The basic problem is that mprotect is very slow under Xen (up to 50x slower than native),

Hi all, [ Change since last post: change name to ptep_modify_prot_, on the grounds that it isn't really a general pte-modification interface. ] This little series adds a new transaction-like abstraction for doing RMW updates to a pte, hooks it into paravirt_ops, and then makes use of it in Xen. The basic problem is that mprotect is very slow under Xen (up to 50x slower than native),

In shadow mode hypervisors, ptep_get_and_clear achieves the desired purpose of keeping the shadows in sync by issuing a native_get_and_clear, followed by a call to pte_update, which indicates the PTE has been modified. Direct mode hypervisors (Xen) have no need for this anyway, and will trap the update using writable pagetables. This means no hypervisor makes use of ptep_get_and_clear; there is

In shadow mode hypervisors, ptep_get_and_clear achieves the desired purpose of keeping the shadows in sync by issuing a native_get_and_clear, followed by a call to pte_update, which indicates the PTE has been modified. Direct mode hypervisors (Xen) have no need for this anyway, and will trap the update using writable pagetables. This means no hypervisor makes use of ptep_get_and_clear; there is

Hi all, This little series adds a new transaction-like abstraction for doing RMW updates to a pte, hooks it into paravirt_ops, and then makes use of it in Xen. The basic problem is that mprotect is very slow under Xen (up to 50x slower than native), primarily because of the ptent = ptep_get_and_clear(mm, addr, pte); ptent = pte_modify(ptent, newprot); /* ... */ set_pte_at(mm, addr, pte,

Hi all, This little series adds a new transaction-like abstraction for doing RMW updates to a pte, hooks it into paravirt_ops, and then makes use of it in Xen. The basic problem is that mprotect is very slow under Xen (up to 50x slower than native), primarily because of the ptent = ptep_get_and_clear(mm, addr, pte); ptent = pte_modify(ptent, newprot); /* ... */ set_pte_at(mm, addr, pte,

Hi all, This little series adds a new transaction-like abstraction for doing RMW updates to a pte, hooks it into paravirt_ops, and then makes use of it in Xen. The basic problem is that mprotect is very slow under Xen (up to 50x slower than native), primarily because of the ptent = ptep_get_and_clear(mm, addr, pte); ptent = pte_modify(ptent, newprot); /* ... */ set_pte_at(mm, addr, pte,

A lot of cleanup after removal of 32-bit Xen PV guest support in paravirt code. Changes in V4: - dropped patches 1-3, as already committed - addressed comments to V3 - added new patches 5+6 Changes in V3: - addressed comments to V2 - split patch 1 into 2 patches - new patches 3 and 7 Changes in V2: - rebase to 5.8 kernel - addressed comments to V1 - new patches 3 and 4 Juergen Gross (6):

Hi Andi, This series of patches updates paravirt_ops in various ways. Some of the changes are plain cleanups and improvements, and some add some interfaces necessary for Xen. The brief overview: add-MAINTAINERS.patch - obvious remove-CONFIG_DEBUG_PARAVIRT.patch - no longer needed paravirt-nop.patch - mark nop operations consistently paravirt-pte-accessors.patch - operations to pack/unpack

Hi Andi, This series of patches updates paravirt_ops in various ways. Some of the changes are plain cleanups and improvements, and some add some interfaces necessary for Xen. The brief overview: add-MAINTAINERS.patch - obvious remove-CONFIG_DEBUG_PARAVIRT.patch - no longer needed paravirt-nop.patch - mark nop operations consistently paravirt-pte-accessors.patch - operations to pack/unpack

Hi Andi, Here's a repost of the paravirt_ops update series I posted the other day. Since then, I found a few potential bugs with patching clobbering, cleaned up and documented paravirt.h and the patching machinery. Overview: add-MAINTAINERS.patch obvious remove-CONFIG_DEBUG_PARAVIRT.patch No longer meaningful or needed. paravirt-nop.patch Clean up nop paravirt_ops functions, mainly to

Hi Andi, Here's a repost of the paravirt_ops update series I posted the other day. Since then, I found a few potential bugs with patching clobbering, cleaned up and documented paravirt.h and the patching machinery. Overview: add-MAINTAINERS.patch obvious remove-CONFIG_DEBUG_PARAVIRT.patch No longer meaningful or needed. paravirt-nop.patch Clean up nop paravirt_ops functions, mainly to

On x86 set_pte_at() is now always falling back to set_pte(). So instead of having this fallback after the paravirt maze just drop the set_pte_at paravirt operation and let set_pte_at() use the set_pte() function directly. Signed-off-by: Juergen Gross <jgross at suse.com> --- arch/x86/include/asm/paravirt.h | 8 +------- arch/x86/include/asm/paravirt_types.h | 2 --

With removal of lguest some of the paravirt functions are no longer needed. Remove them. Signed-off-by: Juergen Gross <jgross at suse.com> --- arch/x86/include/asm/desc.h | 3 +-- arch/x86/include/asm/paravirt.h | 37 ----------------------------------- arch/x86/include/asm/paravirt_types.h | 9 --------- arch/x86/include/asm/pgtable.h | 27

With removal of lguest some of the paravirt functions are no longer needed. Remove them. Signed-off-by: Juergen Gross <jgross at suse.com> --- arch/x86/include/asm/desc.h | 3 +-- arch/x86/include/asm/paravirt.h | 37 ----------------------------------- arch/x86/include/asm/paravirt_types.h | 9 --------- arch/x86/include/asm/pgtable.h | 27

The long term plan has been to replace Xen PV guests by PVH. The first victim of that plan are now 32-bit PV guests, as those are used only rather seldom these days. Xen on x86 requires 64-bit support and with Grub2 now supporting PVH officially since version 2.04 there is no need to keep 32-bit PV guest support alive in the Linux kernel. Additionally Meltdown mitigation is not available in the

The last 32-bit user of stuff under CONFIG_PARAVIRT_XXL is gone. Remove 32-bit specific parts. Signed-off-by: Juergen Gross <jgross at suse.com> --- arch/x86/entry/vdso/vdso32/vclock_gettime.c | 1 + arch/x86/include/asm/paravirt.h | 92 +++------------------ arch/x86/include/asm/paravirt_types.h | 21 ----- arch/x86/include/asm/pgtable-3level_types.h | 5 --

The last 32-bit user of stuff under CONFIG_PARAVIRT_XXL is gone. Remove 32-bit specific parts. Signed-off-by: Juergen Gross <jgross at suse.com> --- arch/x86/entry/vdso/vdso32/vclock_gettime.c | 1 + arch/x86/include/asm/paravirt.h | 120 ++------------------ arch/x86/include/asm/paravirt_types.h | 21 ---- arch/x86/include/asm/pgtable-3level_types.h | 5 -

The long term plan has been to replace Xen PV guests by PVH. The first victim of that plan are now 32-bit PV guests, as those are used only rather seldom these days. Xen on x86 requires 64-bit support and with Grub2 now supporting PVH officially since version 2.04 there is no need to keep 32-bit PV guest support alive in the Linux kernel. Additionally Meltdown mitigation is not available in the