search for: ptep_modify_prot_start

...n. Trapping into the instruction emulator is inherently expensive. And, 2: because ptep_get_and_clear has atomic-fetch-and-update semantics, it's impossible to implement in a way which can be batched to amortize the cost of trapping into the hypervisor. This series adds the ptep_modify_prot_start() and ptep_modify_prot_commit() operations, which change this sequence to: ptent = ptep_modify_prot_start(mm, addr, pte); ptent = pte_modify(ptent, newprot); /* ... */ ptep_modify_prot_commit(mm, addr, pte, ptent); Which looks very familiar. And, indeed, when compiled without CONFIG_PARAVIRT...

...n. Trapping into the instruction emulator is inherently expensive. And, 2: because ptep_get_and_clear has atomic-fetch-and-update semantics, it's impossible to implement in a way which can be batched to amortize the cost of trapping into the hypervisor. This series adds the ptep_modify_prot_start() and ptep_modify_prot_commit() operations, which change this sequence to: ptent = ptep_modify_prot_start(mm, addr, pte); ptent = pte_modify(ptent, newprot); /* ... */ ptep_modify_prot_commit(mm, addr, pte, ptent); Which looks very familiar. And, indeed, when compiled without CONFIG_PARAVIRT...

...n. Trapping into the instruction emulator is inherently expensive. And, 2: because ptep_get_and_clear has atomic-fetch-and-update semantics, it's impossible to implement in a way which can be batched to amortize the cost of trapping into the hypervisor. This series adds the ptep_modify_prot_start() and ptep_modify_prot_commit() operations, which change this sequence to: ptent = ptep_modify_prot_start(mm, addr, pte); ptent = pte_modify(ptent, newprot); /* ... */ ptep_modify_prot_commit(mm, addr, pte, ptent); Which looks very familiar. And, indeed, when compiled without CONFIG_PARAVIRT...

...ravirt_types.h @@ -242,8 +242,6 @@ struct pv_mmu_ops { /* Pagetable manipulation functions */ void (*set_pte)(pte_t *ptep, pte_t pteval); - void (*set_pte_at)(struct mm_struct *mm, unsigned long addr, - pte_t *ptep, pte_t pteval); void (*set_pmd)(pmd_t *pmdp, pmd_t pmdval); pte_t (*ptep_modify_prot_start)(struct vm_area_struct *vma, unsigned long addr, diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index b836138ce852..7414b416779b 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -63,7 +63,6 @@ extern pmdval_t early_pmd_flags; #includ...

...ddr, pte_t *ptep); - void (*pte_update_defer)(struct mm_struct *mm, - unsigned long addr, pte_t *ptep); void (*pmd_update)(struct mm_struct *mm, unsigned long addr, pmd_t *pmdp); - void (*pmd_update_defer)(struct mm_struct *mm, - unsigned long addr, pmd_t *pmdp); pte_t (*ptep_modify_prot_start)(struct mm_struct *mm, unsigned long addr, pte_t *ptep); diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 6ec0c8b..5126367 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -69,9 +69,7 @@ extern struct mm_struct *pgd_page_get...

...ddr, pte_t *ptep); - void (*pte_update_defer)(struct mm_struct *mm, - unsigned long addr, pte_t *ptep); void (*pmd_update)(struct mm_struct *mm, unsigned long addr, pmd_t *pmdp); - void (*pmd_update_defer)(struct mm_struct *mm, - unsigned long addr, pmd_t *pmdp); pte_t (*ptep_modify_prot_start)(struct mm_struct *mm, unsigned long addr, pte_t *ptep); diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 6ec0c8b..5126367 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -69,9 +69,7 @@ extern struct mm_struct *pgd_page_get...

...ddr, pte_t *ptep); - void (*pte_update_defer)(struct mm_struct *mm, - unsigned long addr, pte_t *ptep); - void (*pmd_update)(struct mm_struct *mm, unsigned long addr, - pmd_t *pmdp); - void (*pmd_update_defer)(struct mm_struct *mm, - unsigned long addr, pmd_t *pmdp); pte_t (*ptep_modify_prot_start)(struct mm_struct *mm, unsigned long addr, pte_t *ptep); diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 6ec0c8b..d3eee66 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -69,9 +69,6 @@ extern struct mm_struct *pgd_page_get...

...ddr, pte_t *ptep); - void (*pte_update_defer)(struct mm_struct *mm, - unsigned long addr, pte_t *ptep); - void (*pmd_update)(struct mm_struct *mm, unsigned long addr, - pmd_t *pmdp); - void (*pmd_update_defer)(struct mm_struct *mm, - unsigned long addr, pmd_t *pmdp); pte_t (*ptep_modify_prot_start)(struct mm_struct *mm, unsigned long addr, pte_t *ptep); diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 6ec0c8b..d3eee66 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -69,9 +69,6 @@ extern struct mm_struct *pgd_page_get...

...= paravirt_nop, - .release_pud = paravirt_nop, - .release_p4d = paravirt_nop, + .pv_cpu_ops.alloc_ldt = paravirt_nop, + .pv_cpu_ops.free_ldt = paravirt_nop, - .set_pte = native_set_pte, - .set_pte_at = native_set_pte_at, - .set_pmd = native_set_pmd, + .pv_cpu_ops.load_sp0 = native_load_sp0, - .ptep_modify_prot_start = __ptep_modify_prot_start, - .ptep_modify_prot_commit = __ptep_modify_prot_commit, +#ifdef CONFIG_X86_64 + .pv_cpu_ops.usergs_sysret64 = native_usergs_sysret64, +#endif + .pv_cpu_ops.iret = native_iret, + .pv_cpu_ops.swapgs = native_swapgs, + + .pv_cpu_ops.set_iopl_mask = native_set_iopl_mask, + ....

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):

...mdval); - void (*set_pmd_at)(struct mm_struct *mm, unsigned long addr, - pmd_t *pmdp, pmd_t pmdval); - void (*set_pud_at)(struct mm_struct *mm, unsigned long addr, - pud_t *pudp, pud_t pudval); - void (*pte_update)(struct mm_struct *mm, unsigned long addr, - pte_t *ptep); pte_t (*ptep_modify_prot_start)(struct mm_struct *mm, unsigned long addr, pte_t *ptep); diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 77037b6f1caa..bb8e9ea7deb4 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -43,8 +43,6 @@ extern struct mm_struct *pg...

...mdval); - void (*set_pmd_at)(struct mm_struct *mm, unsigned long addr, - pmd_t *pmdp, pmd_t pmdval); - void (*set_pud_at)(struct mm_struct *mm, unsigned long addr, - pud_t *pudp, pud_t pudval); - void (*pte_update)(struct mm_struct *mm, unsigned long addr, - pte_t *ptep); pte_t (*ptep_modify_prot_start)(struct mm_struct *mm, unsigned long addr, pte_t *ptep); diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 77037b6f1caa..bb8e9ea7deb4 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -43,8 +43,6 @@ extern struct mm_struct *pg...

...t_mm_pinned, + .post_allocator_init = xen_post_allocator_init, }; static const struct pv_time_ops xen_time_ops __initdata = { @@ -1103,7 +1111,7 @@ .set_pte = NULL, /* see xen_pagetable_setup_* */ .set_pte_at = xen_set_pte_at, - .set_pmd = xen_set_pmd, + .set_pmd = xen_set_pmd_hyper, .ptep_modify_prot_start = __ptep_modify_prot_start, .ptep_modify_prot_commit = __ptep_modify_prot_commit, @@ -1117,7 +1125,7 @@ .set_pte_atomic = xen_set_pte_atomic, .set_pte_present = xen_set_pte_at, - .set_pud = xen_set_pud, + .set_pud = xen_set_pud_hyper, .pte_clear = xen_pte_clear, .pmd_clear = xen_pmd_cle...

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 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

Today paravirtualization is a all-or-nothing game: either a kernel is compiled with no paravirtualization support at all, or it is supporting paravirtualized environments like Xen pv-guests or lguest additionally to some paravirtualized tuning for KVM, Hyperv, VMWare or Xen HVM-guests. As support of pv-guests requires quite intrusive pv-hooks (e.g. all access functions to page table entries,

Today paravirtualization is a all-or-nothing game: either a kernel is compiled with no paravirtualization support at all, or it is supporting paravirtualized environments like Xen pv-guests or lguest additionally to some paravirtualized tuning for KVM, Hyperv, VMWare or Xen HVM-guests. As support of pv-guests requires quite intrusive pv-hooks (e.g. all access functions to page table entries,

This series removes some no longer needed stuff from paravirt infrastructure and puts large quantities of paravirt ops under a new config option PARAVIRT_XXL which is selected by XEN_PV only. A pvops kernel without XEN_PV being configured is about 2.5% smaller with this series applied. tip commit 5800dc5c19f34e6e03b5adab1282535cb102fafd ("x86/paravirt: Fix spectre-v2 mitigations for

...,7 @@ struct paravirt_patch_template pv_ops = { .cpu.load_sp0 = native_load_sp0, -#ifdef CONFIG_X86_64 .cpu.usergs_sysret64 = native_usergs_sysret64, -#endif .cpu.iret = native_iret, .cpu.swapgs = native_swapgs, @@ -375,18 +366,11 @@ struct paravirt_patch_template pv_ops = { .mmu.ptep_modify_prot_start = __ptep_modify_prot_start, .mmu.ptep_modify_prot_commit = __ptep_modify_prot_commit, -#if CONFIG_PGTABLE_LEVELS >= 3 -#ifdef CONFIG_X86_PAE - .mmu.set_pte_atomic = native_set_pte_atomic, - .mmu.pte_clear = native_pte_clear, - .mmu.pmd_clear = native_pmd_clear, -#endif .mmu.set_pud = na...

...,7 @@ struct paravirt_patch_template pv_ops = { .cpu.load_sp0 = native_load_sp0, -#ifdef CONFIG_X86_64 .cpu.usergs_sysret64 = native_usergs_sysret64, -#endif .cpu.iret = native_iret, .cpu.swapgs = native_swapgs, @@ -375,18 +366,11 @@ struct paravirt_patch_template pv_ops = { .mmu.ptep_modify_prot_start = __ptep_modify_prot_start, .mmu.ptep_modify_prot_commit = __ptep_modify_prot_commit, -#if CONFIG_PGTABLE_LEVELS >= 3 -#ifdef CONFIG_X86_PAE - .mmu.set_pte_atomic = native_set_pte_atomic, - .mmu.pte_clear = native_pte_clear, - .mmu.pmd_clear = native_pmd_clear, -#endif .mmu.set_pud = na...