From: Christoffer Dall <christoffer.dall@linaro.org> To: "Alex Bennée" <alex.bennee@linaro.org> Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, marc.zyngier@arm.com, peter.maydell@linaro.org, agraf@suse.de, drjones@redhat.com, pbonzini@redhat.com, zhichao.huang@linaro.org, jan.kiszka@siemens.com, dahi@linux.vnet.ibm.com, r65777@freescale.com, bp@suse.de, Gleb Natapov <gleb@kernel.org>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will.deacon@arm.com>, open list <linux-kernel@vger.kernel.org> Subject: Re: [PATCH v5 08/12] KVM: arm64: re-factor hyp.S debug register code Date: Thu, 4 Jun 2015 13:12:48 +0200 [thread overview] Message-ID: <20150604111248.GJ7657@cbox> (raw) In-Reply-To: <87d21bbw3d.fsf@linaro.org> On Thu, Jun 04, 2015 at 11:34:46AM +0100, Alex Bennée wrote: > > Christoffer Dall <christoffer.dall@linaro.org> writes: > > > On Fri, May 29, 2015 at 10:30:24AM +0100, Alex Bennée wrote: > >> This is a pre-cursor to sharing the code with the guest debug support. > >> This replaces the big macro that fishes data out of a fixed location > >> with a more general helper macro to restore a set of debug registers. It > >> uses macro substitution so it can be re-used for debug control and value > >> registers. It does however rely on the debug registers being 64 bit > >> aligned (as they happen to be in the hyp ABI). > > Oops I'd better fix that commit comment. > > >> > >> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > >> > >> --- > >> v3: > >> - return to the patch series > >> - add save and restore targets > >> - change register use and document > >> v4: > >> - keep original setup/restore names > >> - don't use split u32/u64 structure yet > >> --- > >> arch/arm64/kvm/hyp.S | 519 ++++++++++++++------------------------------------- > >> 1 file changed, 140 insertions(+), 379 deletions(-) > >> > >> diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S > >> index 74e63d8..9c4897d 100644 > >> --- a/arch/arm64/kvm/hyp.S > >> +++ b/arch/arm64/kvm/hyp.S > > > > > > [...] > > > >> @@ -465,195 +318,52 @@ > >> msr mdscr_el1, x25 > >> .endm > >> > >> -.macro restore_debug > >> - // x2: base address for cpu context > >> - // x3: tmp register > >> - > >> - mrs x26, id_aa64dfr0_el1 > >> - ubfx x24, x26, #12, #4 // Extract BRPs > >> - ubfx x25, x26, #20, #4 // Extract WRPs > >> - mov w26, #15 > >> - sub w24, w26, w24 // How many BPs to skip > >> - sub w25, w26, w25 // How many WPs to skip > >> - > >> - add x3, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1) > >> +.macro restore_debug type > >> + // x4: pointer to register set > >> + // x5: number of registers to skip > > > > nit: use tabs instead of spaces here... > > > >> + // x6..x22 trashed > >> > > > > [...] > > > >> @@ -887,12 +597,63 @@ __restore_sysregs: > >> restore_sysregs > >> ret > >> > >> +/* Save debug state */ > >> __save_debug: > >> - save_debug > >> + // x0: base address for vcpu context > >> + // x2: ptr to current CPU context > >> + // x4/x5: trashed > > > > I had a bunch of questions here which I think you missed last time > > around: > > 1. why do we need the vcpu context? > > We don't, I'll drop that > > > 2. what does 'current' mean here? > > Either the host or vcpu context depending which way we are currently going. > drop 'current' please. > > 3. you're also trashing everything that save_debug trashes, so x4/5, > > x6-x22 trashed would be more correct > > OK > > > > >> + > >> + mrs x26, id_aa64dfr0_el1 > >> + ubfx x24, x26, #12, #4 // Extract BRPs > >> + ubfx x25, x26, #20, #4 // Extract WRPs > >> + mov w26, #15 > >> + sub w24, w26, w24 // How many BPs to skip > >> + sub w25, w26, w25 // How many WPs to skip > >> + > >> + mov x5, x24 > >> + add x4, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1) > >> + save_debug dbgbcr > >> + add x4, x2, #CPU_SYSREG_OFFSET(DBGBVR0_EL1) > >> + save_debug dbgbvr > >> + > >> + mov x5, x25 > >> + add x4, x2, #CPU_SYSREG_OFFSET(DBGWCR0_EL1) > >> + save_debug dbgwcr > >> + add x4, x2, #CPU_SYSREG_OFFSET(DBGWVR0_EL1) > >> + save_debug dbgwvr > >> + > >> + mrs x21, mdccint_el1 > >> + str x21, [x2, #CPU_SYSREG_OFFSET(MDCCINT_EL1)] > >> ret > >> > >> +/* Restore debug state */ > >> __restore_debug: > >> - restore_debug > >> + // x0: base address for cpu context > >> + // x2: ptr to current CPU context > >> + // x4/x5: trashed > > > > and you missed these comments too, basically same stuff, but why was it > > 'cpu' here and not 'vcpu' like above? > > Again we use the functions both for restoring host and vcpu debug context. > Well, the two functions operate on the same structures, so I would like them to be consistent... -Christoffer
WARNING: multiple messages have this Message-ID (diff)
From: christoffer.dall@linaro.org (Christoffer Dall) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v5 08/12] KVM: arm64: re-factor hyp.S debug register code Date: Thu, 4 Jun 2015 13:12:48 +0200 [thread overview] Message-ID: <20150604111248.GJ7657@cbox> (raw) In-Reply-To: <87d21bbw3d.fsf@linaro.org> On Thu, Jun 04, 2015 at 11:34:46AM +0100, Alex Benn?e wrote: > > Christoffer Dall <christoffer.dall@linaro.org> writes: > > > On Fri, May 29, 2015 at 10:30:24AM +0100, Alex Benn?e wrote: > >> This is a pre-cursor to sharing the code with the guest debug support. > >> This replaces the big macro that fishes data out of a fixed location > >> with a more general helper macro to restore a set of debug registers. It > >> uses macro substitution so it can be re-used for debug control and value > >> registers. It does however rely on the debug registers being 64 bit > >> aligned (as they happen to be in the hyp ABI). > > Oops I'd better fix that commit comment. > > >> > >> Signed-off-by: Alex Benn?e <alex.bennee@linaro.org> > >> > >> --- > >> v3: > >> - return to the patch series > >> - add save and restore targets > >> - change register use and document > >> v4: > >> - keep original setup/restore names > >> - don't use split u32/u64 structure yet > >> --- > >> arch/arm64/kvm/hyp.S | 519 ++++++++++++++------------------------------------- > >> 1 file changed, 140 insertions(+), 379 deletions(-) > >> > >> diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S > >> index 74e63d8..9c4897d 100644 > >> --- a/arch/arm64/kvm/hyp.S > >> +++ b/arch/arm64/kvm/hyp.S > > > > > > [...] > > > >> @@ -465,195 +318,52 @@ > >> msr mdscr_el1, x25 > >> .endm > >> > >> -.macro restore_debug > >> - // x2: base address for cpu context > >> - // x3: tmp register > >> - > >> - mrs x26, id_aa64dfr0_el1 > >> - ubfx x24, x26, #12, #4 // Extract BRPs > >> - ubfx x25, x26, #20, #4 // Extract WRPs > >> - mov w26, #15 > >> - sub w24, w26, w24 // How many BPs to skip > >> - sub w25, w26, w25 // How many WPs to skip > >> - > >> - add x3, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1) > >> +.macro restore_debug type > >> + // x4: pointer to register set > >> + // x5: number of registers to skip > > > > nit: use tabs instead of spaces here... > > > >> + // x6..x22 trashed > >> > > > > [...] > > > >> @@ -887,12 +597,63 @@ __restore_sysregs: > >> restore_sysregs > >> ret > >> > >> +/* Save debug state */ > >> __save_debug: > >> - save_debug > >> + // x0: base address for vcpu context > >> + // x2: ptr to current CPU context > >> + // x4/x5: trashed > > > > I had a bunch of questions here which I think you missed last time > > around: > > 1. why do we need the vcpu context? > > We don't, I'll drop that > > > 2. what does 'current' mean here? > > Either the host or vcpu context depending which way we are currently going. > drop 'current' please. > > 3. you're also trashing everything that save_debug trashes, so x4/5, > > x6-x22 trashed would be more correct > > OK > > > > >> + > >> + mrs x26, id_aa64dfr0_el1 > >> + ubfx x24, x26, #12, #4 // Extract BRPs > >> + ubfx x25, x26, #20, #4 // Extract WRPs > >> + mov w26, #15 > >> + sub w24, w26, w24 // How many BPs to skip > >> + sub w25, w26, w25 // How many WPs to skip > >> + > >> + mov x5, x24 > >> + add x4, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1) > >> + save_debug dbgbcr > >> + add x4, x2, #CPU_SYSREG_OFFSET(DBGBVR0_EL1) > >> + save_debug dbgbvr > >> + > >> + mov x5, x25 > >> + add x4, x2, #CPU_SYSREG_OFFSET(DBGWCR0_EL1) > >> + save_debug dbgwcr > >> + add x4, x2, #CPU_SYSREG_OFFSET(DBGWVR0_EL1) > >> + save_debug dbgwvr > >> + > >> + mrs x21, mdccint_el1 > >> + str x21, [x2, #CPU_SYSREG_OFFSET(MDCCINT_EL1)] > >> ret > >> > >> +/* Restore debug state */ > >> __restore_debug: > >> - restore_debug > >> + // x0: base address for cpu context > >> + // x2: ptr to current CPU context > >> + // x4/x5: trashed > > > > and you missed these comments too, basically same stuff, but why was it > > 'cpu' here and not 'vcpu' like above? > > Again we use the functions both for restoring host and vcpu debug context. > Well, the two functions operate on the same structures, so I would like them to be consistent... -Christoffer
next prev parent reply other threads:[~2015-06-04 11:12 UTC|newest] Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-05-29 9:30 [PATCH v5 00/12] KVM Guest Debug support for arm64 Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-05-29 9:30 ` [PATCH v5 01/12] KVM: add comments for kvm_debug_exit_arch struct Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-05-29 9:30 ` [PATCH v5 02/12] KVM: arm64: fix misleading comments in save/restore Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-05-29 9:30 ` [PATCH v5 03/12] KVM: arm64: guest debug, define API headers Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-06-04 11:07 ` Christoffer Dall 2015-06-04 11:07 ` Christoffer Dall 2015-06-04 11:07 ` Christoffer Dall 2015-06-04 13:49 ` Alex Bennée 2015-06-04 13:49 ` Alex Bennée 2015-06-04 13:49 ` Alex Bennée 2015-06-04 14:40 ` Andrew Jones 2015-06-04 14:40 ` Andrew Jones 2015-05-29 9:30 ` [PATCH v5 04/12] KVM: arm: guest debug, add stub KVM_SET_GUEST_DEBUG ioctl Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-05-29 9:30 ` [PATCH v5 05/12] KVM: arm: introduce kvm_arm_init/setup/clear_debug Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-06-04 11:07 ` Christoffer Dall 2015-06-04 11:07 ` Christoffer Dall 2015-05-29 9:30 ` [PATCH v5 06/12] KVM: arm64: guest debug, add SW break point support Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-05-29 9:30 ` [PATCH v5 07/12] KVM: arm64: guest debug, add support for single-step Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-06-04 11:07 ` Christoffer Dall 2015-06-04 11:07 ` Christoffer Dall 2015-06-04 11:07 ` Christoffer Dall 2015-06-04 13:46 ` Alex Bennée 2015-06-04 13:46 ` Alex Bennée 2015-05-29 9:30 ` [PATCH v5 08/12] KVM: arm64: re-factor hyp.S debug register code Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-06-04 10:23 ` Christoffer Dall 2015-06-04 10:23 ` Christoffer Dall 2015-06-04 10:34 ` Alex Bennée 2015-06-04 10:34 ` Alex Bennée 2015-06-04 10:34 ` Alex Bennée 2015-06-04 11:12 ` Christoffer Dall [this message] 2015-06-04 11:12 ` Christoffer Dall 2015-05-29 9:30 ` [PATCH v5 09/12] KVM: arm64: introduce vcpu->arch.debug_ptr Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-06-04 10:56 ` Christoffer Dall 2015-06-04 10:56 ` Christoffer Dall 2015-06-04 10:56 ` Christoffer Dall 2015-05-29 9:30 ` [PATCH v5 10/12] KVM: arm64: guest debug, HW assisted debug support Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-06-01 9:15 ` Will Deacon 2015-06-01 9:15 ` Will Deacon 2015-06-01 9:15 ` Will Deacon 2015-06-01 12:41 ` Alex Bennée 2015-06-01 12:41 ` Alex Bennée 2015-06-01 12:41 ` Alex Bennée 2015-06-04 11:06 ` Christoffer Dall 2015-06-04 11:06 ` Christoffer Dall 2015-06-04 11:06 ` Christoffer Dall 2015-05-29 9:30 ` [PATCH v5 11/12] KVM: arm64: enable KVM_CAP_SET_GUEST_DEBUG Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-05-29 9:30 ` [PATCH v5 12/12] KVM: arm64: add trace points for guest_debug debug Alex Bennée 2015-05-29 9:30 ` Alex Bennée 2015-05-29 9:30 ` Alex Bennée
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