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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=83fDaIfLsY16yic2+Bpl9lC9hOGkPIV4LchssH1j3LE=; b=lxOM0ay8w2VjHuAUZwLyYQvJLnJ65G3QRMWBkOfeK9cYeMI+tKT+euo4xHsrO4IKip tWaXdbeBZEtaA3tvi1eh16N4el6jO70OhvrVpWdof7P8UV4mKOtbutS37tQbly8KtLMW AdVxbNCJaTH/DSCsj2JApvnGq7fKnQg98jFBWPGHEQGjxb0/FUD08ains1dPFcNONZkV trJEzdERdPnxHT9EIrLX0PKTzmszBU00lRkp8lbsJa7zkPh2vXSw+IPr9YiSD2HZ5Ork Z8T4Yanh8Nr4xcZKDgl8rICYzo3uXjBQE8oQVz+FVss4zGH5fzFSAzGqKiLetvPF+yqI DF4Q== X-Gm-Message-State: AOAM532JBCuEkdZfHVZbUOJq7izOLX+RiaNPk5+C9Ip3Ue4Qe8hVLvUg laMHoRnOeUduBNPE3powxxwPo8Plli0= X-Google-Smtp-Source: ABdhPJzi9q8UGwJAYqkti8laANuUPc3nn5R3eDyiiZDnOVn9vGB1o/QfvD8/gVEEbONDuMag3MzbiMyJaWQ= X-Received: from oupton.c.googlers.com ([fda3:e722:ac3:cc00:2b:ff92:c0a8:404]) (user=oupton job=sendgmr) by 2002:a92:5205:: with SMTP id g5mr634503ilb.22.1628067527974; Wed, 04 Aug 2021 01:58:47 -0700 (PDT) Date: Wed, 4 Aug 2021 08:58:10 +0000 In-Reply-To: <20210804085819.846610-1-oupton@google.com> Message-Id: <20210804085819.846610-13-oupton@google.com> Mime-Version: 1.0 References: <20210804085819.846610-1-oupton@google.com> X-Mailer: git-send-email 2.32.0.605.g8dce9f2422-goog Subject: [PATCH v6 12/21] KVM: arm64: Separate guest/host counter offset values From: Oliver Upton To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu Cc: Paolo Bonzini , Sean Christopherson , Marc Zyngier , Peter Shier , Jim Mattson , David Matlack , Ricardo Koller , Jing Zhang , Raghavendra Rao Anata , James Morse , Alexandru Elisei , Suzuki K Poulose , linux-arm-kernel@lists.infradead.org, Andrew Jones , Will Deacon , Catalin Marinas , Oliver Upton X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210804_015849_536133_5E2C1422 X-CRM114-Status: GOOD ( 17.86 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org In some instances, a VMM may want to update the guest's counter-timer offset in a transparent manner, meaning that changes to the hardware value do not affect the synthetic register presented to the guest or the VMM through said guest's architectural state. Lay the groundwork to separate guest offset register writes from the hardware values utilized by KVM. Signed-off-by: Oliver Upton Reviewed-by: Andrew Jones --- arch/arm64/kvm/arch_timer.c | 48 ++++++++++++++++++++++++++++++++---- include/kvm/arm_arch_timer.h | 3 +++ 2 files changed, 46 insertions(+), 5 deletions(-) diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c index c0101db75ad4..4c2b763a8849 100644 --- a/arch/arm64/kvm/arch_timer.c +++ b/arch/arm64/kvm/arch_timer.c @@ -87,6 +87,18 @@ static u64 timer_get_offset(struct arch_timer_context *ctxt) struct kvm_vcpu *vcpu = ctxt->vcpu; switch(arch_timer_ctx_index(ctxt)) { + case TIMER_VTIMER: + return ctxt->host_offset; + default: + return 0; + } +} + +static u64 timer_get_guest_offset(struct arch_timer_context *ctxt) +{ + struct kvm_vcpu *vcpu = ctxt->vcpu; + + switch (arch_timer_ctx_index(ctxt)) { case TIMER_VTIMER: return __vcpu_sys_reg(vcpu, CNTVOFF_EL2); default: @@ -132,13 +144,31 @@ static void timer_set_offset(struct arch_timer_context *ctxt, u64 offset) switch(arch_timer_ctx_index(ctxt)) { case TIMER_VTIMER: - __vcpu_sys_reg(vcpu, CNTVOFF_EL2) = offset; + ctxt->host_offset = offset; break; default: WARN(offset, "timer %ld\n", arch_timer_ctx_index(ctxt)); } } +static void timer_set_guest_offset(struct arch_timer_context *ctxt, u64 offset) +{ + struct kvm_vcpu *vcpu = ctxt->vcpu; + + switch (arch_timer_ctx_index(ctxt)) { + case TIMER_VTIMER: { + u64 host_offset = timer_get_offset(ctxt); + + host_offset += offset - __vcpu_sys_reg(vcpu, CNTVOFF_EL2); + __vcpu_sys_reg(vcpu, CNTVOFF_EL2) = offset; + timer_set_offset(ctxt, host_offset); + break; + } + default: + WARN_ONCE(offset, "timer %ld\n", arch_timer_ctx_index(ctxt)); + } +} + u64 kvm_phys_timer_read(void) { return timecounter->cc->read(timecounter->cc); @@ -749,7 +779,8 @@ int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu) /* Make offset updates for all timer contexts atomic */ static void update_timer_offset(struct kvm_vcpu *vcpu, - enum kvm_arch_timers timer, u64 offset) + enum kvm_arch_timers timer, u64 offset, + bool guest_visible) { int i; struct kvm *kvm = vcpu->kvm; @@ -758,13 +789,20 @@ static void update_timer_offset(struct kvm_vcpu *vcpu, lockdep_assert_held(&kvm->lock); kvm_for_each_vcpu(i, tmp, kvm) - timer_set_offset(vcpu_get_timer(tmp, timer), offset); + if (guest_visible) + timer_set_guest_offset(vcpu_get_timer(tmp, timer), + offset); + else + timer_set_offset(vcpu_get_timer(tmp, timer), offset); /* * When called from the vcpu create path, the CPU being created is not * included in the loop above, so we just set it here as well. */ - timer_set_offset(vcpu_get_timer(vcpu, timer), offset); + if (guest_visible) + timer_set_guest_offset(vcpu_get_timer(vcpu, timer), offset); + else + timer_set_offset(vcpu_get_timer(vcpu, timer), offset); } static void update_vtimer_cntvoff(struct kvm_vcpu *vcpu, u64 cntvoff) @@ -772,7 +810,7 @@ static void update_vtimer_cntvoff(struct kvm_vcpu *vcpu, u64 cntvoff) struct kvm *kvm = vcpu->kvm; mutex_lock(&kvm->lock); - update_timer_offset(vcpu, TIMER_VTIMER, cntvoff); + update_timer_offset(vcpu, TIMER_VTIMER, cntvoff, true); mutex_unlock(&kvm->lock); } diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h index 51c19381108c..9d65d4a29f81 100644 --- a/include/kvm/arm_arch_timer.h +++ b/include/kvm/arm_arch_timer.h @@ -42,6 +42,9 @@ struct arch_timer_context { /* Duplicated state from arch_timer.c for convenience */ u32 host_timer_irq; u32 host_timer_irq_flags; + + /* offset relative to the host's physical counter-timer */ + u64 host_offset; }; struct timer_map {