RISC V needs CMOs, and hence a CMO Working Group EditNew Page All successful computer instruction sets have Cache Management Operations (CMOs). Several RISC-V systems have already defined implementati

P extension specification has defined a fixed-point saturation flag CSR. We need to allocate it officially in the user standard read/write address range. Should we use the same CSR for V and P extensi

Hello, Background: You may be aware that the RISC-V Debug Specification 0.13 defines two CSRs, mcontext and scontext, that can be used to qualify hardware breakpoints in a particular OS process or thr

Yeah, sure. : ) 发件人: Andrew Waterman [mailto:andrew@...] 发送时间: 2020年8月4日 16:58 收件人: zhaosiqi (A) <zhaosiqi3@...> 抄送: Anup Patel <Anup.Patel@...>; tech-privileged@... 主题: Re: [RISC-V] [tech-privileged]

It's good news we came to the same conclusions independently :)

Thanks for the clarification. It turns out that I was looking at an older code base. 发件人: Anup Patel [mailto:Anup.Patel@...] 发送时间: 2020年8月4日 16:48 收件人: zhaosiqi (A) <zhaosiqi3@...>; Andrew Waterman <a

In that case, yeah, section 3 does not propose anything new. 发件人: Andrew Waterman [mailto:andrew@...] 发送时间: 2020年8月4日 16:40 收件人: zhaosiqi (A) <zhaosiqi3@...> 抄送: tech-privileged@... 主题: Re: [RISC-V] [

The QEMU “virt” machine emulates both TIME CSR and HTIMEDELTA CSR so no trapping happens when accessing TIME and HTIMEDELTA CSRs from VS/VU mode on QEMU. Although, QEMU “sifive_u” machine does not emu

hcounteren.TM is already defined this way, for exactly this purpose.

I see. This is new information for me though. The ‘that is’ in the current spec makes the sentence look like an reiteration of the functionality of the htimedelta itself. I totally didn’t expect this

Yeah, my point is that the current definition of htimedelta already says what you want it to say about the time CSR. Reading the time CSR in VS-mode or VU-mode isn't required to trap, and it returns t

Thanks for the timely comment, we are aware of the htimedelta CSR in the hypervisor spec. Section 3 is meant to propose aliases available in VS-mode and VU-mode. Because they are meant to provide time

Hello Everyone, We have come up with some ideas about improving the performance of virtual machines on the RISC-V architecture. Here’s the first piece which proposes a dedicated clock source and a clo

The satp register has reserved values. Some implementers will, no doubt, want to define non-standard behavior based on satp. I would like to propose that we define some of the reserved values in satp

Hi All, We have updated Spike, QEMU RISC-V, KVM RISC-V and Xvisor RISC-V for RISC-V H-Extension v0.6.1 spec. The QEMU RISC-V is our default development vehicle for RISC-V hypervisor software (because

Hi All, We now have a simple Nested MMU (i.e. Two-stage MMU) test-suite available as part of Xvisor white-box testing framework. This test-suite runs in HS-mode and does nested MMU testing using the H

I would like to get people's views on the question of when is an sfence.vma required after changing the satp.mode field (to see what support there is for the following change/clarification in the Priv

Hi, The mcycle CSR is described in the RISC-V Privileged Architecture spec as: The mcycle CSR counts the number of clock cycles executed by the processor core on which the hart is running. What does '

When address-related exceptions occur, the xTVAL CSR is written with the faulting effective address. However, the spec also says: Implementations may convert some invalid address patterns into other i

We have run across the situation of running "legacy" (i.e. current) boot code that naturally is unaware of the possible existence of the Hypervisor extension. Since, on a platform that does implement