Replace sp->tdp_mmu_page with a bit in the page role. This reduces the size of struct kvm_mmu_page by a byte. Note that in tdp_mmu_init_sp() there is no need to explicitly set sp->role.tdp_mmu=1 for every SP since the role is already copied to all child SPs. Suggested-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> Link: https://lore.kernel.org/kvm/b0e8eb55-c2ee-ce13-8806-9d0184678984@xxxxxxxxxx/ Signed-off-by: David Matlack <dmatlack@xxxxxxxxxx> --- arch/x86/include/asm/kvm_host.h | 11 ++++++++--- arch/x86/kvm/mmu/mmu.c | 1 + arch/x86/kvm/mmu/mmu_internal.h | 1 - arch/x86/kvm/mmu/tdp_mmu.c | 1 - arch/x86/kvm/mmu/tdp_mmu.h | 2 +- 5 files changed, 10 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 4d2bc08794e4..33e5b1c56ff4 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -304,10 +304,10 @@ struct kvm_kernel_irq_routing_entry; * the number of unique SPs that can theoretically be created is 2^n, where n * is the number of bits that are used to compute the role. * - * But, even though there are 19 bits in the mask below, not all combinations + * But, even though there are 20 bits in the mask below, not all combinations * of modes and flags are possible: * - * - invalid shadow pages are not accounted, so the bits are effectively 18 + * - invalid shadow pages are not accounted, so the bits are effectively 19 * * - quadrant will only be used if has_4_byte_gpte=1 (non-PAE paging); * execonly and ad_disabled are only used for nested EPT which has @@ -321,6 +321,10 @@ struct kvm_kernel_irq_routing_entry; * - on top of this, smep_andnot_wp and smap_andnot_wp are only set if * cr0_wp=0, therefore these three bits only give rise to 5 possibilities. * + * - When tdp_mmu=1, only a subset of the remaining bits can vary across + * shadow pages: level, invalid, and smm. The rest are fixed, e.g. direct=1, + * access=ACC_ALL, guest_mode=0, etc. + * * Therefore, the maximum number of possible upper-level shadow pages for a * single gfn is a bit less than 2^13. */ @@ -340,7 +344,8 @@ union kvm_mmu_page_role { unsigned ad_disabled:1; unsigned guest_mode:1; unsigned passthrough:1; - unsigned :5; + unsigned tdp_mmu:1; + unsigned:4; /* * This is left at the top of the word so that diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index aeb240b339f5..458a7c398f76 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -5128,6 +5128,7 @@ kvm_calc_tdp_mmu_root_page_role(struct kvm_vcpu *vcpu, role.level = kvm_mmu_get_tdp_level(vcpu); role.direct = true; role.has_4_byte_gpte = false; + role.tdp_mmu = tdp_mmu_enabled; return role; } diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h index ac00bfbf32f6..49591f3bd9f9 100644 --- a/arch/x86/kvm/mmu/mmu_internal.h +++ b/arch/x86/kvm/mmu/mmu_internal.h @@ -54,7 +54,6 @@ struct kvm_mmu_page { struct list_head link; struct hlist_node hash_link; - bool tdp_mmu_page; bool unsync; u8 mmu_valid_gen; diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index bba33aea0fb0..e0eda6332755 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -280,7 +280,6 @@ static void tdp_mmu_init_sp(struct kvm_mmu_page *sp, tdp_ptep_t sptep, sp->role = role; sp->gfn = gfn; sp->ptep = sptep; - sp->tdp_mmu_page = true; trace_kvm_mmu_get_page(sp, true); } diff --git a/arch/x86/kvm/mmu/tdp_mmu.h b/arch/x86/kvm/mmu/tdp_mmu.h index 0a63b1afabd3..cf7321635ff1 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.h +++ b/arch/x86/kvm/mmu/tdp_mmu.h @@ -71,7 +71,7 @@ u64 *kvm_tdp_mmu_fast_pf_get_last_sptep(struct kvm_vcpu *vcpu, u64 addr, u64 *spte); #ifdef CONFIG_X86_64 -static inline bool is_tdp_mmu_page(struct kvm_mmu_page *sp) { return sp->tdp_mmu_page; } +static inline bool is_tdp_mmu_page(struct kvm_mmu_page *sp) { return sp->role.tdp_mmu; } #else static inline bool is_tdp_mmu_page(struct kvm_mmu_page *sp) { return false; } #endif base-commit: de60733246ff4545a0483140c1f21426b8d7cb7f prerequisite-patch-id: 42a76ce7cec240776c21f674e99e893a3a6bee58 -- 2.39.1.456.gfc5497dd1b-goog
