Re: [PATCH v12 19/37] x86/fred: Update MSR_IA32_FRED_RSP0 during task switch

2023-11-13 Thread H. Peter Anvin
On November 13, 2023 1:29:47 PM EST, Borislav Petkov wrote: >On Mon, Nov 13, 2023 at 12:36:04PM -0500, H. Peter Anvin wrote: >> A resource cannot be consumed after the value has been written; this >> is the only necessary level of serialization, equivalent to, say, RAX. > >Lemme see if I understan

Re: [PATCH v12 19/37] x86/fred: Update MSR_IA32_FRED_RSP0 during task switch

2023-11-13 Thread Borislav Petkov
On Mon, Nov 13, 2023 at 12:36:04PM -0500, H. Peter Anvin wrote: > A resource cannot be consumed after the value has been written; this > is the only necessary level of serialization, equivalent to, say, RAX. Lemme see if I understand this correctly using this context as an example: after this MSR_

Re: [PATCH v12 19/37] x86/fred: Update MSR_IA32_FRED_RSP0 during task switch

2023-11-13 Thread H. Peter Anvin
On November 13, 2023 4:37:42 AM EST, Borislav Petkov wrote: >On Mon, Oct 02, 2023 at 11:24:40PM -0700, Xin Li wrote: >> From: "H. Peter Anvin (Intel)" >> >> MSR_IA32_FRED_RSP0 is used during ring 3 event delivery, and needs to >> be updated to point to the top of next task stack during task swit

Re: [PATCH v12 19/37] x86/fred: Update MSR_IA32_FRED_RSP0 during task switch

2023-11-13 Thread Borislav Petkov
On Mon, Oct 02, 2023 at 11:24:40PM -0700, Xin Li wrote: > From: "H. Peter Anvin (Intel)" > > MSR_IA32_FRED_RSP0 is used during ring 3 event delivery, and needs to > be updated to point to the top of next task stack during task switch. > > Signed-off-by: H. Peter Anvin (Intel) > Tested-by: Shan

[PATCH v12 19/37] x86/fred: Update MSR_IA32_FRED_RSP0 during task switch

2023-10-02 Thread Xin Li
From: "H. Peter Anvin (Intel)" MSR_IA32_FRED_RSP0 is used during ring 3 event delivery, and needs to be updated to point to the top of next task stack during task switch. Signed-off-by: H. Peter Anvin (Intel) Tested-by: Shan Kang Signed-off-by: Xin Li --- arch/x86/include/asm/switch_to.h | 8