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Bae" Content-Type: text/plain; charset="UTF-8" Define regs_{avail,dirty} as bitmaps instead of U32s to harden against overflow, and to allow for dynamically sizing the bitmaps when APX comes along, which will add 16 more GPRs (R16-R31) and thus increase the total number of registers beyond 32. Open code writes in the "reset" APIs, as the writes are hot paths and bitmap_write() is complete overkill for what KVM needs. Even better, hardcoding writes to entry '0' in the array is a perfect excuse to assert that the array contains exactly one entry, e.g. to effectively add guard against defining R16-R31 in 32-bit kernels. For all intents and purposes, no functional change intended even though using bitmap_fill() will mean "undefined" registers are no longer marked available and dirty (KVM should never be querying those bits). Signed-off-by: Sean Christopherson --- arch/x86/include/asm/kvm_host.h | 6 ++++-- arch/x86/kvm/kvm_cache_regs.h | 20 ++++++++++++-------- arch/x86/kvm/x86.c | 4 ++-- 3 files changed, 18 insertions(+), 12 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index c47eb294c066..ef0c368676c5 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -211,6 +211,8 @@ enum kvm_reg { VCPU_REG_SEGMENTS, VCPU_REG_EXIT_INFO_1, VCPU_REG_EXIT_INFO_2, + + NR_VCPU_TOTAL_REGS, }; enum { @@ -802,8 +804,8 @@ struct kvm_vcpu_arch { */ unsigned long regs[NR_VCPU_GENERAL_PURPOSE_REGS]; unsigned long rip; - unsigned long regs_avail; - unsigned long regs_dirty; + DECLARE_BITMAP(regs_avail, NR_VCPU_TOTAL_REGS); + DECLARE_BITMAP(regs_dirty, NR_VCPU_TOTAL_REGS); unsigned long cr0; unsigned long cr0_guest_owned_bits; diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h index 171e6bc2e169..2ae492ad6412 100644 --- a/arch/x86/kvm/kvm_cache_regs.h +++ b/arch/x86/kvm/kvm_cache_regs.h @@ -67,29 +67,29 @@ static inline bool kvm_register_is_available(struct kvm_vcpu *vcpu, enum kvm_reg reg) { kvm_assert_register_caching_allowed(vcpu); - return test_bit(reg, (unsigned long *)&vcpu->arch.regs_avail); + return test_bit(reg, vcpu->arch.regs_avail); } static inline bool kvm_register_is_dirty(struct kvm_vcpu *vcpu, enum kvm_reg reg) { kvm_assert_register_caching_allowed(vcpu); - return test_bit(reg, (unsigned long *)&vcpu->arch.regs_dirty); + return test_bit(reg, vcpu->arch.regs_dirty); } static inline void kvm_register_mark_available(struct kvm_vcpu *vcpu, enum kvm_reg reg) { kvm_assert_register_caching_allowed(vcpu); - __set_bit(reg, (unsigned long *)&vcpu->arch.regs_avail); + __set_bit(reg, vcpu->arch.regs_avail); } static inline void kvm_register_mark_dirty(struct kvm_vcpu *vcpu, enum kvm_reg reg) { kvm_assert_register_caching_allowed(vcpu); - __set_bit(reg, (unsigned long *)&vcpu->arch.regs_avail); - __set_bit(reg, (unsigned long *)&vcpu->arch.regs_dirty); + __set_bit(reg, vcpu->arch.regs_avail); + __set_bit(reg, vcpu->arch.regs_dirty); } /* @@ -102,12 +102,15 @@ static __always_inline bool kvm_register_test_and_mark_available(struct kvm_vcpu enum kvm_reg reg) { kvm_assert_register_caching_allowed(vcpu); - return arch___test_and_set_bit(reg, (unsigned long *)&vcpu->arch.regs_avail); + return arch___test_and_set_bit(reg, vcpu->arch.regs_avail); } static __always_inline void kvm_clear_available_registers(struct kvm_vcpu *vcpu, unsigned long clear_mask) { + BUILD_BUG_ON(sizeof(clear_mask) != sizeof(vcpu->arch.regs_avail[0])); + BUILD_BUG_ON(ARRAY_SIZE(vcpu->arch.regs_avail) != 1); + /* * Note the bitwise-AND! In practice, a straight write would also work * as KVM initializes the mask to all ones and never clears registers @@ -115,12 +118,13 @@ static __always_inline void kvm_clear_available_registers(struct kvm_vcpu *vcpu, * sanity checking as incorrectly marking an eagerly sync'd register * unavailable will generate a WARN due to an unexpected cache request. */ - vcpu->arch.regs_avail &= ~clear_mask; + vcpu->arch.regs_avail[0] &= ~clear_mask; } static __always_inline void kvm_reset_dirty_registers(struct kvm_vcpu *vcpu) { - vcpu->arch.regs_dirty = 0; + BUILD_BUG_ON(ARRAY_SIZE(vcpu->arch.regs_dirty) != 1); + vcpu->arch.regs_dirty[0] = 0; } /* diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index ac05cc289b56..b8a91feec8e1 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12836,8 +12836,8 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) int r; vcpu->arch.last_vmentry_cpu = -1; - vcpu->arch.regs_avail = ~0; - vcpu->arch.regs_dirty = ~0; + bitmap_fill(vcpu->arch.regs_avail, NR_VCPU_TOTAL_REGS); + bitmap_fill(vcpu->arch.regs_dirty, NR_VCPU_TOTAL_REGS); kvm_gpc_init(&vcpu->arch.pv_time, vcpu->kvm); -- 2.53.0.1213.gd9a14994de-goog